CTLA4 binders

ABSTRACT

The present invention provides molecules, such as ISVDs and Nanobodies, that bind to CTLA4 or human serum albumin. These molecules have been engineered so as to reduce the incidence of binding by pre-existing antibodies in the bodies of a subject administered such a molecule. Methods for increasing immune response, treating cancer and/or treating an infectious disease with such molecules are provided.

This application claims the benefit of and is a divisional of U.S.patent application Ser. No. 15/353,886, filed Nov. 17, 2016, whichclaims the benefit of U.S. Provisional Patent Application No.62/257,001, filed Nov. 18, 2015; both of which are incorporated byreferenced in its entirety.

REFERENCE TO SEQUENCE LISTING SUBMITTED ELECTRONICALLY

The sequence listing of the present application is submittedelectronically via EFS-Web as an ASCII formatted sequence listing with afile name “24237_US_DIV_SEQTXT_11FEBRUARY2020.txt”, creation date ofFeb. 11, 2020, and a size of 103 Kb. This sequence listing submitted viaEFS-Web is part of the specification and is herein incorporated byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates, in part, to amino acid sequences andpolypeptides binding to cytotoxic T-lymphocyte-associated protein 4(“CTLA4”), e.g., human CTLA4. In particular, the present inventionrelates, in part, to improved heavy-chain immunoglobulin single variabledomains (also referred to herein as “ISVs” or “ISVDs”) binding to CTLA4,as well as to proteins, polypeptides and other constructs, compounds,molecules or chemical entities that comprise such ISVDs. Other aspects,embodiments, features, uses and advantages of the invention will beclear to the skilled person based on the disclosure herein.

BACKGROUND OF THE INVENTION

Abrogating immune regulatory molecules such as cytotoxic T lymphocyteantigen 4 (CTLA-4) represents a new and promising strategy to inducetumor regression, stabilize disease, and prolong survival bymanipulation of the immune system. An anti-CTLA-4 antibody, ipilimumab,is currently being sold for indications including melanoma. Evidence oftumor regression with prolonged time to progression has been seen inpatients with melanoma who received CTLA-4 antibodies and durableresponses have been observed with ipilimumab in patients with melanoma,ovarian cancer, prostate cancer, and renal cell cancer.

Full T-cell activation requires two signals. The first is initiated byT-cell receptor binding to tumor-associated antigens presented byantigen presenting cells (APCs) via major histocompatibility complexes Iand II. The second signal is generated when the principal costimulatoryreceptor on the T cell, CD28, binds to B7 ligand subtypes CD80 and CD86on the APC. The resulting dual signaling induces changes includingT-cell proliferation and cytokine release, triggering and thenamplifying the immune response. In response to T-cell activation, CTLA-4is upregulated and competes with CD28 for CD80 and CD86 binding on APCsbut with significantly higher affinity, therefore downregulating—ordeactivating—the T cell (FIG. 1 ). CTLA-4, therefore, downregulatesT-cell responses and APC function, resulting in a decreased immuneresponse to tumor-associated antigens and immune tolerance.

The mechanisms whereby CTLA4 and PD1 exert their inhibitory effects onT-cell activation are multifaceted. CTLA4 functions primarily to limitT-cell activation and clonal expansion, whereas PD1 functions primarilyto limit effector T-cell function in the peripheral tissues. Theirdistinct molecular structures, regulation, signaling pathways, liganddistribution, and function on Tregs and other immune cells suggest thatcombined therapeutic blockade of CTLA4 and PD1 could synergize tomediate anti-tumor immunity. Intlekofer & Thompson, J. Leuko. Biol.94(1): 25-39 (2013); Hurwitz et al. Proc. Natl. Acad. Sci. USA 95:10067-10071 (1998); Parry et al. Mol. Cell. Biol. 25(21): 9543-9553(2005); Callahan et al. Front. Oncol. Vol 4, Art. 385 (2015).

One method by which to inhibit CTLA4-mediated downregulation is byinterfering with its interaction with its ligands by binding it with aNanobody. The possibility exists that Nanobodies, originating in llamas,could cause an unwanted anti-drug immune response, e.g., by binding ofthe Nanobodies by pre-existing antibodies in the patient's serum. Thus,novel methods by which to humanize Nanobodies so as to decrease oreliminate such a response are particularly valuable as are Nanobodiesthat are created by such methods.

SUMMARY OF THE INVENTION

The present invention provides a multispecific immunoglobulin singlevariable domain (ISVD) such as a Nanobody that binds to human CTLA4 bycontacting human CTLA4 at one or more of the following residues VRVTVL(SEQ ID NO: 118; amino acids 33-38 of SEQ ID NO: 110), ADSQVTEVC (SEQ IDNO: 119; amino acids 41-49 of SEQ ID NO: 110) and CKVELMYPPPYYLG (SEQ IDNO: 120; amino acids 93-106 of SEQ ID NO: 110), e.g., all three sites.For example, the binder protects the residues from hydrogen-deuteriumexchange in the presence of a deuterium source such as D₂O. In anembodiment of the invention, the ISVD binds to human CTLA4 and generatesa binding heat map (e.g., as generated in a hydrogen-dueterium exchangeassay) essentially as set forth in FIG. 13 .

The present invention also provides a CTLA4 binder comprising one ormore (e.g., 2) immunoglobulin single variable domains (ISVDs) that bindto human CTLA4 comprising: CDR1 that comprises the amino acid sequenceFYGMG (SEQ ID NO: 2; amino acids 6-10 of SEQ ID NO: 5) or GGTFSFYGMG(SEQ ID NO: 5); CDR2 that comprises the amino acid sequenceDIRTSAGRTYYADSVKG (SEQ ID NO: 3) or DIRTSAGRTY (SEQ ID NO: 6; aminoacids 1-10 of SEQ ID NO: 3); CDR3 that comprises the amino acid sequenceEXSGISGWDY (SEQ ID NO: 4; wherein X is M or P); optionally, wherein theISVD comprises a mutation at residues 11 and 89 (e.g., L11V and/or V89L,for example (E1D, L11V, A14P, Q45R, A74S, K83R, V89L, M96P, Q108L)wherein said residue numbers are Kabat residue numbers.

The present invention provides a CTLA4 binder (e.g., an ISVD, e.g., aNanobody) comprising CDR1, CDR2 and CDR3 of an immunoglobulin comprisingamino acid sequence set forth in SEQ ID NO: 1 wherein said CTLA4 bindercomprises at least one mutation with respect to the amino acid sequenceset forth in SEQ ID NO: 1 wherein said at least one mutation is at aposition selected from the group consisting of 11, 89, 110 and 112,wherein said positions are numbered according to Kabat; and optionallyincluding any number of additional mutations that are set forth hereinor otherwise, e.g. up to 10 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10)additional mutations (e.g., point mutations, substitutions, deletions,insertions). For example, in an embodiment of the invention, CDR1comprises the amino acid sequence: FYGMG (SEQ ID NO: 2) or GGTFSFYGMG(SEQ ID NO: 5); CDR2 comprises the amino acid sequence:DIRTSAGRTYYADSVKG (SEQ ID NO: 3) or DIRTSAGRTY (SEQ ID NO: 6); and CDR3comprises the amino acid sequence: EMSGISGWDY (SEQ ID NO: 115). Forexample, in an embodiment of the invention, the CTLA4 binder has amutation relative to SEQ ID NO: 1 wherein the amino acid residue atposition 11 is chosen from L or V; the amino acid residue at position 89is suitably chosen from T, V or L; the amino acid residue at position110 is suitably chosen from T, K or Q; and/or the amino acid residue atposition 112 is suitably chosen from S, K or Q; e.g., wherein themutation is 89T; 89L in combination with 11V; 89L in combination with110K or 110Q; 89L in combination with 112K or 112Q; 89L in combinationwith 11V and 110K or 110Q; 89L in combination with 11V and 112K or 112Q;11V in combination with 110K or 110Q; and/or 11V in combination with112K or 112Q. In an embodiment of the invention, the mutation atpositions 11, 89, 110 and/or 112 is as set forth in Table B. In anembodiment of the invention, the CTLA4 binder further comprises one ormore mutations, relative to the SEQ ID NO: 1, at positions 1, 14, 45,74, 83 and/or 108. In an embodiment of the invention, the CTLA4 binderhas a C-terminal extension of 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 aminoacids. For example, in the embodiment of the invention, the C-terminalextension has the formula —X(n), wherein X and n are as follows: (a) n=1and X=Ala; (b) n=2 and each X=Ala; (c) n=3 and each X=Ala; (d) n=2 andat least one X=Ala (with the remaining amino acid residue(s) X beingindependently chosen from any naturally occurring amino acid); (e) n=3and at least one X=Ala (with the remaining amino acid residue(s) X beingindependently chosen from any naturally occurring amino acid); (f) n=3and at least two X=Ala (with the remaining amino acid residue(s) X beingindependently chosen from any naturally occurring amino acid); (g) n=1and X=Gly; (h) n=2 and each X=Gly; (i) n=3 and each X=Gly; (j) n=2 andat least one X=Gly (with the remaining amino acid residue(s) X beingindependently chosen from any naturally occurring amino acid); (k) n=3and at least one X=Gly (with the remaining amino acid residue(s) X beingindependently chosen from any naturally occurring amino acid); (l) n=3and at least two X=Gly (with the remaining amino acid residue(s) X beingindependently chosen from any naturally occurring amino acid); (m) n=2and each X=Ala or Gly; (n) n=3 and each X=Ala or Gly; (o) n=3 and atleast one X=Ala or Gly (with the remaining amino acid residue(s) X beingindependently chosen from any naturally occurring amino acid); or (p)n=3 and at least two X=Ala or Gly (with the remaining amino acidresidue(s) X being independently chosen from any naturally occurringamino acid). For example, in an embodiment of the invention, theC-terminal extension is A, AA, AAA, G, GG, GGG, AG, GA, AAG, AGG, AGA,GGA, GAA or GAG. The present invention includes a CTLA4 binder (e.g., anISVD such as a Nanobody) which comprises an amino acid sequence havingat least 85% (e.g., 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97,98, 99, 99.5, 99.9 or 100%) sequence identity with the amino acidsequence set forth in a member selected from the group consisting of SEQID NOs: 8-43 wherein the CTLA4 binder or ISVD comprises CDR1, CDR2 andCDR3 of an immunoglobulin comprising an amino acid sequence set forth inSEQ ID NO: 1 wherein said CTLA4 binder or ISVD comprises at least onemutation with respect to the amino acid sequence set forth in SEQ ID NO:1 wherein said at least one mutation is at a position selected from thegroup consisting of 11, 89, 110 and 112, wherein said positions arenumbered according to Kabat. The present invention also provides a CTLA4binder, ISVD, Nanobody or polypeptide comprising the amino acid sequenceselected from the group consisting of SEQ ID NOs: 9-40. The presentinvention also provides a multispecific binder comprising a CTLA4binding moiety (e.g., an ISVD such as a Nanobody) that binds to CTLA4which is linked to one or more molecules that bind to an epitope that isnot the epitope to which the CTLA4 binding moiety binds (e.g., PD1,CTLA4, LAG3, BTLA and/or CD27).

The present invention also provides any such CTLA4 binder, polypeptide,immunoglobulin single variable domain (ISVD) or multispecific binderwhich is in association with a further therapeutic agent.

The present invention also provides an injection device (e.g.,hypodermic needle and syringe) or vessel that comprises the CTLA4binder, immunoglobulin single variable domain (ISVD), Nanobody,polypeptide or multispecific binder optionally in association with afurther therapeutic agent.

The present invention also provides a polynucleotide encoding the CTLA4binder, immunoglobulin single variable domain (ISVD), Nanobody,polypeptide or multispecific binder, e.g., which is in a vector. Thepresent invention also provides a host cell (e.g., a CHO cell or Pichiacell) comprising the polynucleotide or vector.

The present invention also provides a method for making an CTLA4 binder,immunoglobulin single variable domain (ISVD), Nanobody, polypeptide ormultispecific binder comprising introducing a polynucleotide encodingthe CTLA4 binder, immunoglobulin single variable domain (ISVD),Nanobody, polypeptide or multispecific binder into a host cell (e.g., aCHO cell or Pichia cell) and culturing the host cell in a medium underconditions favorable to expression of said immunoglobulin from saidpolynucleotide and, optionally, purifying the immunoglobulin from saidhost cell and/or said medium. Any immunoglobulin single variable domain(ISVD), Nanobody, polypeptide, multispecific binder or CTLA4 binderproduced by such a method.

The present invention also provides a method for preventing CTLA4 on aT-cell from binding to CD80 and/or CD86 on an antigen-presenting cellcomprising contacting said CTLA4 with an immunoglobulin single variabledomain (ISVD), Nanobody, polypeptide, multispecific binder or CTLA4binder optionally in association with a further therapeutic agent. Thepresent invention also provides a method for enhancing an immuneresponse in the body of a subject comprising administering an effectiveamount of an immunoglobulin single variable domain (ISVD), Nanobody,polypeptide, multispecific binder or CTLA4 binder to the subject (e.g.,mammal such as a human) optionally in association with a furthertherapeutic agent. The present invention also provides a method fortreating or preventing cancer or an infectious disease in the body of asubject comprising administering an effective amount of animmunoglobulin single variable domain (ISVD), Nanobody, polypeptide,multispecific binder or CTLA4 binder optionally in association with afurther therapeutic agent to the subject. In an embodiment of theinvention, the cancer is metastatic cancer, a solid tumor, a hematologiccancer, leukemia, lymphoma, osteosarcoma, rhabdomyosarcoma,neuroblastoma, kidney cancer, leukemia, renal transitional cell cancer,bladder cancer, Wilm's cancer, ovarian cancer, pancreatic cancer, breastcancer, prostate cancer, bone cancer, lung cancer, non-small cell lungcancer, gastric cancer, colorectal cancer, cervical cancer, synovialsarcoma, head and neck cancer, squamous cell carcinoma, multiplemyeloma, renal cell cancer, retinoblastoma, hepatoblastoma,hepatocellular carcinoma, melanoma, rhabdoid tumor of the kidney,Ewing's sarcoma, chondrosarcoma, brain cancer, glioblastoma, meningioma,pituitary adenoma, vestibular schwannoma, a primitive neuroectodermaltumor, medulloblastoma, astrocytoma, anaplastic astrocytoma,oligodendroglioma, ependymoma, choroid plexus papilloma, polycythemiavera, thrombocythemia, idiopathic myelfibrosis, soft tissue sarcoma,thyroid cancer, endometrial cancer, carcinoid cancer or liver cancer,breast cancer or gastric cancer. In an embodiment of the invention, theinfectious disease is a bacterial infection, a viral infection or afungal infection. For example, in an embodiment of the invention, thesubject is administered a further therapeutic agent or a therapeuticprocedure in association with the immunoglobulin single variable domain(ISVD), Nanobody, polypeptide, multispecific binder or CTLA4 binder.

The present invention provides a CTLA4 binder (e.g., a multivalentbinder) comprising an immunoglobulin single variable domain (ISVD) thatbinds to human CTLA4 by contacting human CTLA4 at one or more of thefollowing residues: VRVTVL (SEQ ID NO: 118; amino acids 33-38 of SEQ IDNO: 110), ADSQVTEVC (SEQ ID NO: 119; amino acids 41-49 of SEQ ID NO:110) and CKVELMYPPPYYLG (SEQ ID NO:120; amino acids 93-106 of SEQ ID NO:110); wherein the ISVD comprises a mutation at residues 11 (e.g., L11V)and 89 (e.g., V89L) wherein said residue numbers are Kabat residuenumbers.

The present invention also provides a CTLA4 binder (e.g., a multivalentbinder) comprising an immunoglobulin single variable domain (ISVD) thatbinds to CTLA4 comprising the amino acid sequence set forth in SEQ IDNO: 1 but comprising one or more mutations at a position selected fromthe group consisting of E1, L11, A14, Q45, A74, N73, K83, V89, M96 orQ108L (e.g., E1D, L11V, A14P, Q45R, A74S, N73X (wherein X is S, V, G, R,Q, M, H, T, D, E, W, F, K, A, Y or P), K83R, V89L, M96P, Q108L); whereinsaid residue numbers are Kabat residue numbers; and, optionally, ahalf-life extender (e.g., ALB 11002) and/or a C-terminal extender (e.g.,an Alanine). For example, in an embodiment of the invention, the ISVDcomprises the amino acid sequence: XVQLVESGGGVVQPGGSLRLSCAASGGTFSFYGMGWFRQAPGKEREFVADIRTSAGRTYYADSVKGRFTISRDNSKNTVYLQMNSLRPEDTALYYCAAEPSGISGWDYWGQGTLVTVSS, wherein X is D or E (SEQ ID NO: 60); optionally comprising ahalf-life extender (e.g., ALB 11002) and/or a C-terminal extender (e.g.,an Alanine). In an embodiment of the invention, the CTLA4 bindercomprises an ISVD that includes the amino acid sequence selected fromSEQ ID NOs: 93-109; optionally lacking amino acidsAAADYKDHDGDYKDHDIDYKDDDDKGAAHHHHHH thereof. In an embodiment of theinvention, the CTLA4 binder comprises an ISVD that binds to CTLA4comprising the amino acid sequence set forth in SEQ ID NO: 60 wherein Xis D or E; a peptide linker (e.g., GGGGSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGS(SEQ ID NO: 65)); an ISVD that binds to CTLA4 comprising the amino acidsequence set forth in SEQ ID NO: 60 wherein X is D or E; a peptidelinker; a half-life extender; and, optionally, a C-terminal extensionalanine; or wherein the CTLA4 binder comprises an ISVD that binds toCTLA4 comprising the amino acid sequence set forth in SEQ ID NO: 60wherein X is D or E; a peptide linker; a half-life extender; and,optionally, a C-terminal extension alanine. In an embodiment of theinvention, the CTLA4 binder comprises the amino acid sequence:

(SEQ ID NO: 62) DVQLVESGGGVVQPGGSLRLSCAASGGTFSFYGMGWFRQAPGKEREFVADIRTSAGRTYYADSVKGRFTISRDNSKNTVYLQMNSLRPEDTALYYCAAEPSGISWDYWGQGTLVTVSSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGGSEVQLVESGGGVVQPGGSLRLSCAASGGTFSFYGMGWFRQAPGKEREFVADIRTSAGRTYYADSVKGRFTISRDNSKNTVYLQMNSLRPEDTALYYCAAEPSGISGWDYWGQGTLVTVSSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSEVQLVESGGGVVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTALYYCTIGGSLSRSSQGTLVTVSSA; or (SEQ ID NO: 64)DVQLVESGGGVVQPGGSLRLSCAASGGTFSFYGMGWFRQAPGKEREFVADIRTSAGRTYYADSVKGRFTISRDNSKNTVYLQMNSLRPEDTALYYCAAEPSGISGWDYWGQGTLVTVSSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSEVQLVESGGGVVQPGNSLRLSCAASGETFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTALYYC TIGGSLSRSSQGTLVTVSSA.

The present invention also provides a binder (e.g., an antibody) thatcross-blocks a CTLA4 binder set forth herein from binding to CTLA4.

The present invention also provides an injection device or vessel thatcomprises any CTLA4 binder set forth herein (e.g., comprising the aminoacid sequence set forth in SEQ ID NO: 62 or 64) optionally inassociation with a further therapeutic agent.

The present invention also provides a polynucleotide (e.g., DNA)encoding any CTLA4 binder set forth herein (e.g., comprising the aminoacid sequence set forth in SEQ ID NO: 62 or 64); e.g., comprising thenucleotide sequence of SEQ ID NO: 61 or 63; or a vector comprising sucha polynucleotide; or a host cell comprising such a polynucleotide orvector.

The present invention also provides a method for making the CTLA4 binderset forth herein (e.g., comprising the amino acid sequence set forth inSEQ ID NO: 62 or 64) comprising introducing a polynucleotide encodingthe CTLA4 binder into a host cell (e.g., a CHO cell or Pichia cell) andculturing the host cell in a medium under conditions favorable toexpression of said CTLA4 binder from said polynucleotide and,optionally, purifying the CTLA4 binder from said host cell and/or saidmedium as well as any CTLA4 binder produced by such a method.

The present invention also provides a method for preventing CTLA4 frombinding to CD80 or CD86 (e.g., in the body of a subject) comprisingcontacting said CTLA4 with the CTLA4 binder (e.g., comprising the aminoacid sequence set forth in SEQ ID NO: 62 or 64) optionally inassociation with a further therapeutic agent; as well as a method forenhancing an immune response in the body of a subject (e.g., a human)comprising administering an effective amount of the CTLA4 binder (e.g.,comprising the amino acid sequence set forth in SEQ ID NO: 62 or 64) tothe subject optionally in association with a further therapeutic agent(e.g., pembrolizumab). In addition, the present invention provides amethod for treating or preventing cancer or an infectious disease in thebody of a subject comprising administering an effective amount of CTLA4binder (e.g., comprising the amino acid sequence set forth in SEQ ID NO:62 or 64) optionally in association with a further therapeutic agent(e.g., pembrolizumab) to the subject. In an embodiment of the invention,the cancer is metastatic cancer, a solid tumor, a hematologic cancer,leukemia, lymphoma, osteosarcoma, rhabdomyosarcoma, neuroblastoma,kidney cancer, leukemia, renal transitional cell cancer, bladder cancer,Wilm's cancer, ovarian cancer, pancreatic cancer, breast cancer,prostate cancer, bone cancer, lung cancer, non-small cell lung cancer,gastric cancer, colorectal cancer, cervical cancer, synovial sarcoma,head and neck cancer, squamous cell carcinoma, multiple myeloma, renalcell cancer, retinoblastoma, hepatoblastoma, hepatocellular carcinoma,melanoma, rhabdoid tumor of the kidney, Ewing's sarcoma, chondrosarcoma,brain cancer, glioblastoma, meningioma, pituitary adenoma, vestibularschwannoma, a primitive neuroectodermal tumor, medulloblastoma,astrocytoma, anaplastic astrocytoma, oligodendroglioma, ependymoma,choroid plexus papilloma, polycythemia vera, thrombocythemia, idiopathicmyelfibrosis, soft tissue sarcoma, thyroid cancer, endometrial cancer,carcinoid cancer or liver cancer, breast cancer or gastric cancer; orwherein the infectious disease is a bacterial infection, a viralinfection or a fungal infection. In an embodiment of the invention, thesubject is administered a further therapeutic agent (e.g.,pembrolizumab) or a therapeutic procedure in association with the CTLA4binder.

DESCRIPTION OF THE FIGURES

FIG. 1 . A table listing some of the amino acid positions that will bespecifically referred to herein and their numbering according to somealternative numbering systems (such as Aho and IMGT)

FIG. 2-1-2-5 . CTLA4 binder sequences.

FIG. 3 (A-B). Alignment of 11F1 sequence with that of the SEQ ID NOs:8-43.

FIG. 4 . Predominant N-linked glycans for monoclonal antibodies producedin Chinese hamster ovary cells (CHO N-linked glycans) and in engineeredyeast cells (engineered yeast N-linked glycans): squares:N-acetylglucosamine (GlcNac); circles: mannose (Man); diamonds:galactose (Gal); triangles: fucose (Fuc).

FIG. 5 (A-B). bFACS analysis of Nanobody F023700912, F023700925 orcontrol nanobody (IRR00051; anti-HER2/ERBB2 (bivalent anti-HER2 with35GS connected to albumin binder)) binding to (A) Jurkat and (B) CHO-K1cells expressing hCTLA4.

FIG. 6 (A-B). Competition between Nanobody F023700912 or ipilimumab and(A) CD80 or (B) CD86 for binding to human CTLA4 expressed on CHO-K1cells.

FIG. 7 (A-H). Specificity assessment of Nanobody F023700912, F023700925or control nanobody (IRR00051) for binding to BTLA, CD8, PD1, CTLA4,LAG3, CD28 or control cells. Binding of the Nanobodies was determined to(A) negative control L cells, (B) negative control CHO-K1 cells, (C)huCD28+ L cells, (D) huCD8alpha+ L cells, (E) huLag-3+ CHO-K1 cells, (F)huBTLA+ CHO-K1 cells, (G) huCTLA-4+ CHO-K cells, and (H) huPD-1+ CHO-K1cells.

FIG. 8 (A-B). Competition between Nanobody F023700906, F023701051,F02371054 or F023701061 and (A) human CD80 or (B) human CD86 for bindingto human CTLA-4 expressed on CHO-K1 cells.

FIG. 9 (A-S). Nanobody effect on panc 08.13 tumors in humanized mice.(A) average tumor volumes±SEM and (B) individual tumor volumes on day-37in mice treated with isotype control, ipilimumab (N297A), ipilimumab,pembrolizumab, ipilimumab+pembrolizumab, F023700912 at 5 mpk dosage(CTLA4 Nab-5), F023700912 at 15 mpk dosage (CTLA4 Nab-15), orpembrolizumab+CTLA4 Nab-15; and tumor volumes in individual mice overthe course of the experiment in mice treated with (C) isotype controlantibody, (D) ipilimumab (N297A), (E) ipilimuamb, (F) pembrolizumab, (G)ipilimumab+pembrolizumab, (H) CTLA4 Nab-5, (I) CTLA4 Nab-15 or (J) CTLA4Nab-15+pembrolizumab; (K-S) average (mean±SEM) and individual bodyweight changes in each treatment group.

FIG. 10 (A-B). Serum preAb reactivity to F023700912 and F023700925 and atrivalent control Nanobody T013700112 (lacking mutations to reducepre-existing antibody binding) by (A) healthy human subject sera and (B)cancer patient sera.

FIG. 11 . CTLA4 binder constructs.

FIG. 12 (A-C). CTLA4 binder sequences.

FIG. 13 . Deuterium labeling difference heatmap of human CTLA4 bindingby F023700912 CTLA4 binder.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides ISVDs that comprise mutations which blockreactivity of pre-existing antibodies (pre-antibodies) to neo-epitopeswithin the ISVDs. Neoepitopes are epitopes within a protein which arerevealed when the protein is mutated (e.g., truncated) or its folding isaltered. Pre-existing antibodies are antibodies existing in the body ofa patient prior to receipt of an ISVD. The ISVDs of the presentinvention are based, in part, in llama antibodies whose C-terminalconstant domains have been removed; thus, exposing the neo-epitopes inthe C-terminus of the resulting VHH to pre-antibody binding. It has beendiscovered that the combination of mutations of residues 11 and 89(e.g., L11V and 189L or V89L) led to a surprising lack of pre-antibodybinding. Mutations in residue 112 have also been shown to remarkablyreduce pre-antibody binding. Buyse & Boutton (WO2015/173325) includeddata showing that the combination of an L11V and V89L mutation provideda remarkable improvement in reducing pre-antibody binding compared to anL11V mutation alone or a V89L mutation alone. For example, Table H ofBuyse & Boutton on page 97 showed comparative data for an ISVD with aV89L mutation alone (with or without C-terminal extension) and the sameISVD with a V89L mutation in combination with an L11V mutation (again,with or without a C-terminal extension). Also, although generated in twoseparate experiments, the data shown in Table H for the L11V/V89Lcombination as compared to the data given in Table B for an L11Vmutation alone (in the same ISVD) showed that the pre-antibody bindingreduction that is obtained by the L11V/V89L combination was greater thanthat for the L11V mutation alone. Since the llama antibody scaffoldstructure is known to be very highly conserved, the effect of themutations at positions 11 and 89 is very likely to exist for any ISVD.Indeed, the effect was demonstrated, in FIG. 10 , with the instantbinders, F023700912 and F023700925, which were shown to exhibit very lowlevels of pre-antibody binding.

In the present application, the amino acid residues/positions in animmunoglobulin heavy-chain variable domain will be indicated with thenumbering according to Kabat. For the sake of convenience, FIG. 1 givesa table listing some of the amino acid positions that will bespecifically referred to herein and their numbering according to somealternative numbering systems (such as Aho and IMGT. Note: unlessexplicitly indicated otherwise, for the present description and claims,Kabat numbering is decisive; other numbering systems are given forreference only).

With regards to the CDRs, as is well-known in the art, there aremultiple conventions to define and describe the CDRs of a VH or VHHfragment, such as the Kabat definition (which is based on sequencevariability and is the most commonly used) and the Chotia definition(which is based on the location of the structural loop regions).Reference is for example made to the website www.boinf.org.uk/abs/. Forthe purposes of the present specification and claims, even though theCDRs according to Kabat may also be mentioned, the CDRs are mostpreferably defined on the basis of the Abm definition (which is based onOxford Molecular's AbM antibody modelling software), as this isconsidered to be an optimal compromise between the Kabat and Chotiadefinitions. Reference is again made to the websitewww.bioinf.org.uk/abs/. See Sequences of Proteins of ImmunologicalInterest, Kabat, et al.; National Institutes of Health, Bethesda, Md.;5th ed.; NIH Publ. No. 91-3242 (1991); Kabat (1978) Adv. Prot. Chem.32:1-75; Kabat, et al., (1977) J. Biol. Chem. 252:6609-6616; Chothia, etal., (1987) J Mol. Biol. 196:901-917 or Chothia, et al., (1989) Nature342:878-883; Chothia & Lesk (1987) J. Mol. Biol. 196: 901-917; Elvin A.Kabat, Tai Te Wu, Carl Foeller, Harold M. Perry, Kay S. Gottesman (1991)Sequences of Proteins of Immunological Interest; Protein Sequence andStructure Analysis of Antibody Variable Domains. In: AntibodyEngineering Lab Manual (Ed.: Duebel, S. and Kontermann, R.,Springer-Verlag, Heidelberg). In an embodiment of the invention, CDRdetermination is according to Kabat, e.g., wherein FR1 of a VHHcomprises the amino acid residues at positions 1-30, CDR1 of a VHHcomprises the amino acid residues at positions 31-35, FR2 of a VHHcomprises the amino acids at positions 36-49, CDR2 of a VHH comprisesthe amino acid residues at positions 50-65, FR3 of a VHH comprises theamino acid residues at positions 66-94, CDR3 of a VHH comprises theamino acid residues at positions 95-102, and FR4 of a VHH comprises theamino acid residues at positions 103-113.

In an embodiment of the invention, CDRs are determined according toKontermann and Diibel (Eds., Antibody Engineering, vol 2, SpringerVerlag Heidelberg Berlin, Martin, Chapter 3, pp. 33-51, 2010).

The term “immunoglobulin single variable domain” (also referred to as“ISV” or “ISVD”) is generally used to refer to immunoglobulin variabledomains (which may be heavy chain or light chain domains, including VH,VHH or VL domains) that can form a functional antigen-binding sitewithout interaction with another variable domain (e.g. without a VH/VLinteraction as is required between the VH and VL domains of conventional4-chain monoclonal antibody). Examples of ISVDs will be clear to theskilled person and for example include Nanobodies (including a VHH, ahumanized VHH and/or a camelized VHs such as camelized human VHs),IgNAR, domains, (single domain) antibodies (such as dAbs™) that are VHdomains or that are derived from a VH domain and (single domain)antibodies (such as dAbs™) that are VL domains or that are derived froma VL domain. ISVDs that are based on and/or derived from heavy chainvariable domains (such as VH or VHH domains) are generally preferred.Most preferably, an ISVD will be a Nanobody. For example, F023700906 isan ISVD.

The term “Nanobody” is generally as defined in WO 2008/020079 or WO2009/138519, and thus in a specific aspect generally denotes a VHH, ahumanized VHH or a camelized VH (such as a camelized human VH) orgenerally a sequence optimized VHH (such as e.g. optimized for chemicalstability and/or solubility, maximum overlap with known human frameworkregions and maximum expression). It is noted that the terms Nanobody orNanobodies are registered trademarks of Ablynx N. V. and thus may alsobe referred to as Nanobody® and/or Nanobodies®).

A multispecific binder is a molecule that comprises a first CTLA4binding moiety (e.g., an ISVD or a Nanobody) and one or more (e.g., 1,2, 3, 4, 5) additional binding moieties (e.g., an ISVDs or Nanobodies)that bind to an epitope other than that of the first CTLA4 bindingmoiety (e.g., a different epitope of CTLA4, or to CD27, LAG3, PD1 orBTLA).

A binding moiety or binding domain or binding unit is a molecule, suchas an ISVD or Nanobody (e.g., any of SEQ ID NOs: 8-43 or 60), that bindsto an antigen such as CTLA4. A binding moiety or binding domain orbinding unit may be part of a larger molecule such as a multivalent ormultispecific binder that includes more than one moiety, domain or unitwhich may comprises another functional element, such as, for example, ahalf-life extender (HLE), targeting unit and/or a small molecule such apolyethyleneglycol (PEG).

A monovalent CTLA4 binder (e.g., ISVD such as a Nanobody) is a moleculethat comprises a single antigen-binding domain. A bivalent CTLA4 binder(e.g., ISVD such as a Nanobody) comprises two antigen-binding domains. Amultivalent CTLA4 binder comprises more than one antigen-binding domain(e.g., 1, 2, 3, 4, 5, 6, or 7).

A monospecific CTLA4 binder (e.g., ISVD such as a Nanobody) binds asingle antigen (CTLA4); a bispecific CTLA4 binder binds to two differentantigens and a multispecific CTLA4 binder binds to more than oneantigen.

A biparatopic CTLA4 binder (e.g., ISVD such as a Nanobody) ismonospecific but binds to two different epitopes of the same antigen. Amultiparatopic CTLA4 binder binds the same antigen but to more than oneepitope in the antigen.

The term “half-life” as used herein in relation to a CTLA4 binder (e.g.,ISVD such as a Nanobody) or other molecule can generally be defined asdescribed in paragraph o) on page 57 of WO 2008/020079 and as mentionedtherein refers to the time taken for the serum concentration of theamino acid sequence, CTLA4 binder, compound or polypeptide to be reducedby 50%, in vivo, for example due to degradation of the sequence orcompound and/or clearance or sequestration of the sequence or compoundby natural mechanisms. The in vivo half-life of an amino acid sequence,CTLA4 binder, compound or polypeptide of the invention can be determinedin any manner known per se, such as by pharmacokinetic analysis.Suitable techniques will be clear to the person skilled in the art, andmay for example generally be as described in paragraph o) on page 57 ofWO 2008/020079. As also mentioned in paragraph o) on page 57 of WO2008/020079, the half-life can be expressed using parameters such as thet½-alpha, t½-beta and the area under the curve (AUC). In this respect itshould be noted that the term “half-life” as used herein in particularrefers to the t½-beta or terminal half-life (in which the t½-alphaand/or the AUC or both may be kept out of considerations). Reference isfor example made to the Experimental Part below, as well as to thestandard handbooks, such as Kenneth, A et al: Chemical Stability ofPharmaceuticals: A Handbook for Pharmacists and Peters et al,Pharmacokinete analysis: A Practical Approach (1996). Reference is alsomade to “Pharmacokinetics”, M Gibaldi & D Perron, published by MarcelDekker, 2nd Rev. edition (1982). Similarly, the terms “increase inhalf-life” or “increased half-life” are also as defined in paragraph o)on page 57 of WO 2008/020079 and in particular refer to an increase inthe t½-beta, either with or without an increase in the t½-alpha and/orthe AUC or both.

When a term is not specifically defined herein, it has its usual meaningin the art, which will be clear to the skilled person. Reference is forexample made to the standard handbooks, such as Sambrook et al,“Molecular Cloning: A Laboratory Manual” (2nd. Ed.), Vols. 1-3, ColdSpring Harbor Laboratory Press (1989); F. Ausubel et al, eds., “Currentprotocols in molecular biology”, Green Publishing and WileyInterscience, New York (1987); Lewin, “Genes II”, John Wiley & Sons, NewYork, N.Y., (1985); Old et al., “Principles of Gene Manipulation: AnIntroduction to Genetic Engineering”, 2nd edition, University ofCalifornia Press, Berkeley, Calif. (1981); Roitt et al., “Immunology”(6th. Ed.), Mosby/Elsevier, Edinburgh (2001); Roitt et al., Roitt'sEssential Immunology, 10th Ed. Blackwell Publishing, U K (2001); andJaneway et al., “Immunobiology” (6th Ed.), Garland SciencePublishing/Churchill Livingstone, New York (2005), as well as to thegeneral background art cited herein.

For a general description of multivalent and multispecific polypeptidescontaining one or more Nanobodies and their preparation, reference isalso made to Conrath et al., J. Biol. Chem., Vol. 276, 10. 7346-7350,2001; Muyldermans, Reviews in Molecular Biotechnology 74 (2001),277-302; as well as to for example WO 1996/34103, WO 1999/23221, WO2004/041862, WO 2006/122786, WO 2008/020079, WO 2008/142164 or WO2009/068627.

“Isolated” CTLA4 binders (e.g., ISVD such as a Nanobody), polypepotides,polynucleotides and vectors, are at least partially free of otherbiological molecules from the cells or cell culture from which they areproduced. Such biological molecules include nucleic acids, proteins,lipids, carbohydrates, or other material such as cellular debris andgrowth medium. An “isolated” CTLA4 binder may further be at leastpartially free of expression system components such as biologicalmolecules from a host cell or of the growth medium thereof. Generally,the term “isolated” is not intended to refer to a complete absence ofsuch biological molecules or to an absence of water, buffers, or saltsor to components of a pharmaceutical formulation that includes theantibodies or fragments.

The phrase “control sequences” refers to polynucleotides necessary forthe expression of an operably linked coding sequence in a particularhost organism. The control sequences that are suitable for prokaryotes,for example, include a promoter, optionally an operator sequence, and aribosome binding site. Eukaryotic cells are known to use promoters,polyadenylation signals, and enhancers.

A nucleic acid or polynucleotide is “operably linked” when it is placedinto a functional relationship with another polynucleotide. For example,DNA for a presequence or secretory leader is operably linked to DNA fora polypeptide if it is expressed as a preprotein that participates inthe secretion of the polypeptide; a promoter or enhancer is operablylinked to a coding sequence if it affects the transcription of thesequence; or a ribosome binding site is operably linked to a codingsequence if it is positioned so as to facilitate translation. Generally,but not always, “operably linked” means that the DNA sequences beinglinked are contiguous, and, in the case of a secretory leader,contiguous and in reading phase. However, enhancers do not have to becontiguous. Linking is accomplished by ligation at convenientrestriction sites. If such sites do not exist, the syntheticoligonucleotide adaptors or linkers are used in accordance withconventional practice.

“Human serum albumin binders” or “HSA binders” of the present inventionare any of the molecules described herein that bind to HSA (e.g., anISVD such as a Nanobody) as well as any antibody or antigen-bindingfragment thereof that binds to HSA and includes any of the HSA bindingmoieties described herein. An individual HSA binder may be referred tohas a HSA binding moiety if it is part of a larger molecule, e.g., amultivalent molecule such as F023700912 or F023700914

In general, the basic antibody structural unit comprises a tetramer.Each tetramer includes two identical pairs of polypeptide chains, eachpair having one “light” (about 25 kDa) and one “heavy” chain (about50-70 kDa). The amino-terminal portion of each chain includes a variableregion of about 100 to 110 or more amino acids primarily responsible forantigen recognition. The carboxy-terminal portion of the heavy chain maydefine a constant region primarily responsible for effector function.Typically, human light chains are classified as kappa and lambda lightchains. Furthermore, human heavy chains are typically classified as mu,delta, gamma, alpha, or epsilon, and define the antibody's isotype asIgM, IgD, IgG, IgA, and IgE, respectively. Within light and heavychains, the variable and constant regions are joined by a “J” region ofabout 12 or more amino acids, with the heavy chain also including a “D”region of about 10 more amino acids. See generally, FundamentalImmunology Ch. 7 (Paul, W., ed., 2nd ed. Raven Press, N.Y. (1989).

Examples of antigen-binding fragments include, but are not limited to,Fab, Fab′, F(ab′)₂, and Fv fragments, and single-chain Fv molecules.

The following properties are associated with the indicated mutations inthe CTLA4 binder 11F01:

E1D: Prevent pyroglutamic acid formation in the first amino acid of theconstruct E1

L11V: Decrease pre-antibody binding

A14P: Humanization

Q45R: Mutated to increase stability

A74S: Humanization

K83R: Humanization

189L: Decrease pre-antibody binding

M96P, Q or R: Prevent oxidation of M96

Q108L: Humanization

In an embodiment of the invention, CTLA4 is human CTLA4. In anembodiment of the invention, human CTLA4 comprises the amino acidsequence:

(SEQ ID NO: 111) MACLGFQRHK AQLNLATRTW PCTLLFFLLF IPVFCKAMHVAQPAVVLASS RGIASFVCEY ASPGKATEVR VTVLRQADSQVTEVCAATYM MGNELTFLDD SICTGTSSGN QVNLTIQGLRAMDTGLYICK VELMYPPPYY LGIGNGTQIY VIDPEPCPDSDFLLWILAAV SSGLFFYSFL LTAVSLSKML KKRSPLTTGV YVKMPPTEPE CEKQFQPYFI PIN

CTLA4 Binders

The present invention aims to provide improved CTLA4 binders, inparticular improved CTLA4 ISVDs and more in particular improved CTLA4Nanobodies. CTLA4 binders of the present invention include polypeptideswhich are variants of polypeptides comprising the amino acid sequence ofSEQ ID NO: 1 which is mutated at position such as 1, 11, 14, 45, 74, 83,89, 96, 108, 110 and/or 112.

A CTLA4 binder or CTLA4 ISVD or CTLA4 Nanobody refers to a binder, ISVDor Nanobody, respectively, that binds to CTLA4.

The improved CTLA4 binders provided by the invention are also referredto herein as the “CTLA4 binders of the invention” or “CTLA4 binders”.These terms encompass any molecule comprising a molecule that is setforth herein which binds to CTLA4. For example, the terms include anISVD that comprises an amino acid sequence set forth in a memberselected from the group consisting of SEQ ID NOs: 8-43 and 60 as well asany polypeptide, Nanobody, ISVD, fusion protein, conventional antibodyor antigen-binding fragment thereof that includes an amino acid sequenceset forth in a member selected from the group consisting of SEQ ID NOs:8-43 and 60; or any bispecific molecule (e.g., an ISVD) that comprisesan amino acid sequence set forth in a member selected from the groupconsisting of SEQ ID NOs: 8-43 and 60, binds to CTLA4 and also binds toanother antigen or another epitope such as CD27, LAG3, PD1, or BTLA. ACTLA4 binder of the present invention is F023700912 or F023700914.

The scope of the present invention includes any CTLA4 binder comprisingthe arrangement of binding moieties set forth in FIG. 11 , optionallylacking the FLAG3 and/or HIS6 tags; as well as any of the amino acidsequences set forth in FIG. 12 .

WO 2008/071447 describes Nanobodies that can bind to CTLA4 and usesthereof. SEQ ID NO: 1306 of WO 2008/071447 disclosed a CTLA4 specificNanobody called 11F01, the sequence of which is given herein as SEQ IDNO: 1. This sequence (also referred to herein as “Reference A”) and itsCDRs are also given in Table A-1 below.

As further described herein, the CTLA4 binders of the invention whichare, in an embodiment of the invention in multivalent and/ormultispecific CTLA4 binders of the present invention (e.g., F023700914),preferably have the same combination of CDRs (i.e. CDR1, CDR2 and CDR3)as are present in 11F01 or in a binder comprising the sequence of 11F01(SEQ ID NO: 1). See Table A-1.

The present invention also includes CTLA4 binders which are variants of11F01 which comprise an amino acid sequence as set forth below in TableA-2 below. The scope of the present invention includes CTLA4 bindersthat include CDR1, CDR2 and CDR3 of said varaints set forth below inTable A-2.

In addition, the present invention multispecific and/or multivalentbinders (e.g., F023700914) comprising a CTLA4 binding moiety thatincludes CDR1, CDR2 and CDR3 or the amino acid sequence of 11F01 or ofone of its varaints set forth below in Table A-2.

TABLE A-1 CTLA4 Nanobody 11F1 (11F01). SEQ ID NO Description Sequence 1Reference A EVQLVESGGGLVQAGGSLRLSCAASGGT WO 2008/071447 FS FYGMGWFRQAPGKEQEFVA DIRTSAG SEQ ID NO: 1306 RTYYADSVKGRFTISRDNAKNTVYLQMN(11F01 or SLKPEDTAVYYCAA EMSGISGWDY WGQG 4CTLA011F01) TQVTVSS

TABLE A-2 Variant CTLA4 Nanobody 11F1. 60 11F01 (E1D,DVQLVESGGGVVQPGGSLRLSCAASGGTFS FYG L11V, A14P, MG WFRQAPGKEREFVADIRTSAGRTYYADSVKG Q45R, A74S, RFTISRDNSKNTVYLQMNSLRPEDTALYYCAA EK83R, V89L, PSGISGWDY WGQGTLVTVSS M96P, Q108L) (F023700906)  2CDR1 (Kabat) FYGMG  (amino acids 6-10 of SEQ ID NO: 5)  3 CDR2 (Kabat)DIRTSAGRTYYADSVKG  4 CDR3 EXSGISGWDY ; wherein X is M or P (Kabat/Abm)(e.g., EmSGISGWDY (SEQ ID NO: 115) or EpSGISGWDY (SEQ ID NO: 116))  5CDR1 (Abm) GGTFS FYGMG  6 CDR2 (Abm) DIRTSAGRTY  (amino acids 1-10 ofSEQ ID NO: 3)  7 CDR3 EXSGISGWDY; wherein X is M or P (Kabat/Abm)(e.g., EmSGSIGWDY (SEQ ID NO: 115) or EpSGSIGWDY (SEQ ID NO: 116)) Note:SEQ ID NO: 4 is identical to SEQ ID NO: 7 *CDRs underscored and/or bold

Residue 1 of SEQ ID NO: 60 can be D or E. If residue 1 is D, the CTLA4binder may be designated as 1D and if residue 1 is E, the CTLA4 bindermay be designated as 1E.

In an embodiment of the invention, a CTLA4 binder of the presentinvention comprises an N73X mutation wherein X is any amino acid otherthan N, e.g., S, V, G, R, Q, M, H, T, D, E, W, F, K, A, Y or P (or anyamino acid other than N).

The present invention includes CTLA4 binders comprising one, two orthree of the CDRs of a CTLA4 binder wherein each comprises 0, 1, 2, 3,4, 5, 6, 7, 8, 9 or 10 amino acid substitutions, e.g., conservativesubstitutions, and/or comprises 100, 99, 98, 97, 96 or 95% sequenceidentity relative to the CDRs that are in the CTLA4 binder sequences setforth of Table A-1 or A-2 (e.g., 11F01 (E1D, L11V, A14P, Q45R, A74S,K83R, V89L, M96P, Q108L) or 11F01), or are set forth in SEQ ID NOs: 2-7,wherein a CTLA4 binder having such CDRs retains the ability to bind toCTLA4.

The Kabat residue numbers for certain residues of the CTLA4 binders(e.g., ISVD such as a Nanobody) that are based on Reference A which areset forth herein are shown in the sequence below:

(SEQ ID NO: 1)

VQLVESGGG

GGSLRLSCAAS

FYGMG

APGKE

DIRTSAGRTYYADSVKG

KNTVYLQM

CAAE

SGISGWDY

The Kabat residue numbers for certain residues of the CTLA4 binder 11F01(E1D, L11V, A14P, Q45R, A74S, K83R, V89L, M96P, Q108L) which are setforth herein are shown in the sequence below:

(SEQ ID NO: 117)

VQLVESGGG 

VQ

GGSLRLSCAASGGTFSFYGMGWFRQAPG KE 

EFVADIRTSAGRTYYADSVKGRFTISRDN 

KNTVYLQMNS L 

PEDTA 

YYCAAE 

SGISGWDYWGQGT

VTVSS

The present invention includes any CTLA4 binder comprising the aminoacid sequence of SEQ ID NO: 60 or an amino acid sequence comprising 80%or more (e.g., 85%, 90%, 95%, 96%, 97%, 98% or 99%) amino acid sequenceidentity wherein the CTLA4 binder retains the ability to bind to CTLA4.

The present invention includes embodiments wherein the CDR3 methionineof a CTLA4 binder, at Kabat position 96, is substituted with any aminoacid such as Proline (but not with Cys, Asp or Asn), e.g., with any ofthe following amino acids: Leu, Ile, Val, Ala, Gly, Tyr, Trp, Phe, Glu,Gln, Ser, Thr, His, Arg, Lys or Pro.

Some preferred, but non-limiting CTLA4 binders (e.g., ISVD such as aNanobody) of the invention are SEQ ID NO: 60 or are listed in FIG. 2 asSEQ ID NOs: 8-43. FIG. 3 shows an alignment of these sequences withReference A (SEQ ID NO: 1). Of these CTLA4 binders, the binders of SEQID NOs:26-43 are examples of CTLA4 binders of the invention having aC-terminal alanine extension, i.e. an alanine residue at the C-terminalend of the ISVD-sequence (also sometimes referred to as “position 114”)compared to the usual C-terminal sequence VTVSS (SEQ ID NO: 57, aspresent in Reference A). As described in WO 2012/175741 (but also forexample in WO 2013/024059 and PCT/EP2015/060643 (WO2015/173325)), thisC-terminal alanine extension can prevent the binding of so-called“pre-existing antibodies” (assumed to be IgGs) to a putative epitopethat is situated at the C-terminal region of the ISV. This epitope isassumed to include, among other residues, the surface-exposed amino acidresidues of the C-terminal sequence VTVSS (SEQ ID NO: 57) as well as theamino acid residue at position 14 (and the amino acid residuesnext/close to the same in the amino acid sequence, such as positions 11,13 and 15) and may also comprise the amino acid residue at position 83(and the amino acid residues next/close to the same in the amino acidsequence, such as positions 82, 82a, 82b and 84) and/or the amino acidresidue at position 108 (and the amino acid residues next/close to thesame in the amino acid sequence, such as position 107).

However, although the presence of such a C-terminal alanine (or aC-terminal extension generally) can greatly reduce (and in a lot ofcases even essentially fully prevent) the binding of the “pre-existingantibodies” that can be found in the sera from a range of subjects (bothhealthy subjects as well as patients), it has been found that the serafrom some subjects (such as the sera from patients with some immunediseases such as SLE) can contain pre-existing antibodies that can bindto the C-terminal region of an ISV (when such region is exposed) evenwhen the ISV contains such a C-terminal alanine (or more generally, suchC-terminal extension). Reference is again made to the co-pendingnon-prepublished PCT application PCT/EP2015/060643 (WO2015/173325) byAblynx N. V. filed on May 13, 2015 and entitled “Improved immunoglobulinvariable domains”.

Accordingly, one specific objective of the invention is to provide CTLA4binders (e.g., ISVD such as a Nanobody) that are improved variants ofthe CTLA4 Nanobody referred to herein as “Reference A” and that havereduced binding by so-called “pre-existing antibodies”, and inparticular of the kind described in PCT/EP2015/060643 (WO2015/173325)(i.e. those pre-existing antibodies that can bind to an exposedC-terminal region of an ISV even in the presence of a C-terminalextension).

The invention provides CTLA4 binders comprising amino acid sequencesthat are variants of the sequence of SEQ ID NO: 1 which comprise one ormore of the following mutations compared to the sequence of SEQ ID NO:1:

-   -   1D or 1E;    -   11V;    -   14P;    -   45R;    -   74S;    -   83R;    -   89L or 89T;    -   96P; or    -   108L;        for example, wherein the CTLA4 binder comprises one or more of        the sets of mutations below:    -   89L in combination with 11V; 14P; 45R; 74S; 83R; 86P; 108L and        1E or 1D;    -   89L in combination with 11V;    -   89L in combination with 110K or 110Q;    -   89L in combination with 112K or 112Q;    -   89L in combination with 11V; 14P; 45R; 74S; 83R; 86P; 108L, 110K        or 110Q and 1E or 1D;    -   89L in combination with 11V; 14P; 45R; 74S; 83R; 86P; 108L, 112K        or 112Q and 1E or 1D;    -   89L in combination with 11V and 110K or 110Q;    -   89L in combination with 11V and 112K or 112Q;    -   11V in combination with 110K or 110Q; and/or    -   11V in combination with 112K or 112Q.

In particular, in an embodiment of the invention, CTLA4 binders (e.g.,ISVD such as a Nanobody) comprise:

-   -   the amino acid at position 1 is preferably E or D;    -   the amino acid at position 11 is preferably L or V;    -   the amino acid at position 14 is preferably A or P;    -   the amino acid at position 45 is preferably Q or R;    -   the amino acid at position 74 is preferably A or S;    -   the amino acid at position 83 is preferably K or R;    -   the amino acid at position 89 is preferably T, V or L;    -   the amino acid at position 96 is preferably M or P;    -   the amino acid at position 108 is preferably Q or L;    -   the amino acid residue at position 110 is preferably suitably        chosen from T, K or Q; and    -   the amino acid residue at position 112 is preferably suitably        chosen from S, K or Q; such that, for example, one or more of        the following is true:    -   (i) position 89 is T;    -   (ii) position 89 is L;    -   (iii) position 1 is D or E, position 11 is V, position 14 is P,        position 45 is R, position 74 is S, position 83 is R, position        89 is L, position 96 is P, and position 108 is L;    -   (iv) position 89 is L and position 11 is V;    -   (v) position 89 is L and position 110 is K or Q;    -   (vi) position 89 is L and position 112 is K or Q;    -   (vii) position 1 is D or E, position 11 is V, position 14 is P,        position 45 is R, position 74 is S, position 83 is R, position        89 is L, position 96 is P, position 108 is L; and position 110        is K or Q;    -   (viii) position 1 is D or E, position 11 is V, position 14 is P,        position 45 is R, position 74 is S, position 83 is R, position        89 is L, position 96 is P, position 108 is L; and position 112        is K or Q;    -   (ix) position 89 is L and position 11 is V and position 110 is K        or Q;    -   (x) position 89 is L and position 11 is V and position 112 is K        or Q;    -   (xi) position 11 is V and position 110 is K or Q; or    -   (xii) position 11 is V and position 112 is K or Q.

In particular embodiments, the CTLA4 binders (e.g., an ISVD such as aNanobody) of the invention comprise amino acid sequences that arevariants of SEQ ID NO: 1 in which position 89 is T or in which position1 is D, position 11 is V, position 14 is P, position 45 is R, position74 is S, position 83 is R, position 89 is L, position 96 is P andposition 108 is L or in which position 11 is V and position 89 is L(optionally in suitable combination with a 110K or 110Q mutation and/ora 112K or 112Q mutation, and in particular in combination with a 110K or110Q mutation) are particularly preferred. Even more preferred are aminoacid sequences in which position 11 is V and position 89 is L,optionally with a 110K or 110Q mutation.

As mentioned, the CTLA4 binders (e.g., ISVD such as a Nanobody)described herein can bind (and in particular, can specifically bind) toCTLA4. In an embodiment of the invention, CTLA4 binders can bind toCTLA4 and thereby prevent CD80, and CD86 on antigen-presenting cellsfrom binding to CTLA-4 on T cells. In an embodiment of the invention,the resulting blockade of CTLA-4 signaling prolongs T-cell activation,restores T-cell proliferation, and thus amplifies T-cell-mediatedimmunity, which theoretically enhances the patient's capacity to mountan antitumor immune response.

In an embodiment of the invention, a CTLA4 binder of the presentinvention, has one or more of the following properties:

-   -   Binds to CTLA4 (e.g., human and/or cynomolgous monkey CTLA4        (CTLA4-Fc fusion protein), e.g., with a K_(D) of about 1 nM        (e.g., 1.2 nM);    -   Binds to CTLA4 on the surface of a cell, e.g., a CHO cell        expressing CTLA4;    -   Blocks binding of CD80 or CD86 to CTLA4 (e.g., CTLA4 expressed        on CHO cells);    -   Does not bind to BTLA, CD8, PD1, LAG3, and/or CD28;    -   Binds in vitro and/or in vivo to human, rhesus monkey and mouse        serum albumin (when fused to one or more ALB 11002 binders);    -   Inhibits tumor growth (e.g., of pancreatic tumors, e.g., human        pancreatic tumors in a mouse harboring human immune cells)

Table B lists some non-limiting possible combinations of the amino acidresidues that can be present at positions 11, 89, 110 and 112 (of SEQ IDNO: 1) in the CTLA4 binders (e.g., ISVD such as a Nanobody) of theinvention.

TABLE B Possible Combinations of Mutations at Amino Acid Positions 11, 89, 110 and 112 in CTLA4 Binder Variants of SEQ ID NO: 1. POSITION 11 89 110 112 Combination L TT S L T T K L T T Q L T K S L T Q S L V T K L V T Q L V K S L V Q S L LT K L L T Q L L K S L L Q S V T T S V T T K V T T Q V T K S V T Q S V VT K V V T Q V V K S V V Q S V L T S V L T K V L T Q V L K S V L Q S

The CTLA4 binders (e.g., ISVD such as a Nanobody) provided by theinvention are further as described in the description, examples andfigures herein, i.e. they have CDRs that are as described herein andhave an overall degree of sequence identity (as defined herein) with thesequence of SEQ ID NO: 1 that is as disclosed herein and/or may have alimited number of “amino acid differences” (as described herein) with(one of) these reference sequences.

The CTLA4 binders (e.g., ISVD such as a Nanobody) of the inventionpreferably comprise the following CDRs (according to the Kabatconvention):

-   -   a CDR1 (according to Kabat) that comprises the amino acid        sequence FYGMG (SEQ ID NO: 2); and    -   a CDR2 (according to Kabat) that comprises the amino acid        sequence DIRTSAGRTYYADSVKG (SEQ ID NO: 3); and    -   a CDR3 (according to Kabat) that comprises the amino acid        sequence EPSGISGWDY (SEQ ID NO: 116); optionally, wherein CDR1,        CDR2 and/or CDR3 comprises 1, 2, 3, 4, 5, 5, 6, 7, 8, 9 or 10        substitutions, e.g., conservative substitutions.

Alternatively, when the CDRs are given according to the Abm convention,the CTLA4 binders (e.g., ISVD such as a Nanobody) of the inventionpreferably comprise the following CDRs:

-   -   a CDR1 (according to Abm) that is the amino acid sequence        GGTFSFYGMG (SEQ ID NO: 5); and    -   a CDR2 (according to Abm) that is the amino acid sequence        DIRTSAGRTY (SEQ ID NO: 6); and    -   a CDR3 (according to Abm) that is the amino acid sequence        EPSGISGWDY (SEQ ID NO: 116, which is the same as SEQ ID NO: 4        when X is P); optionally, wherein CDR1, CDR2 and/or CDR3        comprises 1, 2, 3, 4, 5, 5, 6, 7, 8, 9 or 10 substitutions,        e.g., conservative substitutions.

A CTLA4 binder (e.g., ISVD such as a Nanobody) of the invention, in anembodiment of the invention, has such CDRs and mutations at positions 1,11, 14, 45, 74, 83, 89, 96, 108, 110 and/or 112, as discussed hereinand, optionally:

-   -   a degree of sequence identity with the amino acid sequence of        SEQ ID NO: 1 of at least 85%, preferably at least 90%, more        preferably at least 95% (in which the CDRs, any C-terminal        extension that may be present, as well as the mutations at        positions 1, 11, 14, 45, 74, 83, 89, 96, 108, 110 and/or 112        required by the specific aspect involved are not taken into        account for determining the degree of sequence identity) when        the comparison is performed by a BLAST algorithm wherein the        parameters of the algorithm are selected to give the largest        match between the respective sequences over the entire length of        the respective reference sequences (e.g., expect threshold: 10;        word size: 3; max matches in a query range: 0; BLOSUM 62 matrix;        gap costs: existence 11, extension 1; conditional compositional        score matrix adjustment); and/or    -   no more than 7, such as no more than 5, preferably no more than        3, such as only 3, 2 or 1 “amino acid differences” with the        amino acid sequence of SEQ ID NO: 1 (in which said amino acid        differences, if present, may be present in the frameworks and/or        the CDRs but are preferably present only in the frameworks and        not in the CDRs; not taking into account any C-terminal        extension that may be present and not taking into account the        mutations at positions 1, 11, 14, 45, 74, 83, 89, 96, 108, 110        and/or 112 required by the specific aspect involved).

The following references relate to BLAST algorithms often used forsequence analysis: BLAST ALGORITHMS: Altschul et al. (2005) FEBS J.272(20): 5101-5109; Altschul, S. F., et al., (1990) J. Mol. Biol.215:403-410; Gish, W., et al., (1993) Nature Genet. 3:266-272; Madden,T. L., et al., (1996) Meth. Enzymol. 266:131-141; Altschul, S. F., etal., (1997) Nucleic Acids Res. 25:3389-3402; Zhang, J., et al., (1997)Genome Res. 7:649-656; Wootton, J. C., et al., (1993) Comput. Chem.17:149-163; Hancock, J. M. et al., (1994) Comput. Appl. Biosci.10:67-70; ALIGNMENT SCORING SYSTEMS: Dayhoff, M. O., et al., “A model ofevolutionary change in proteins.” in Atlas of Protein Sequence andStructure, (1978) vol. 5, suppl. 3. M. O. Dayhoff (ed.), pp. 345-352,Natl. Biomed. Res. Found., Washington, D.C.; Schwartz, R. M., et al.,“Matrices for detecting distant relationships.” in Atlas of ProteinSequence and Structure, (1978) vol. 5, suppl. 3.” M. O. Dayhoff (ed.),pp. 353-358, Natl. Biomed. Res. Found., Washington, D.C.; Altschul, S.F., (1991) J. Mol. Biol. 219:555-565; States, D. J., et al., (1991)Methods 3:66-70; Henikoff, S., et al., (1992) Proc. Natl. Acad. Sci. USA89:10915-10919; Altschul, S. F., et al., (1993) J. Mol. Evol.36:290-300; ALIGNMENT STATISTICS: Karlin, S., et al., (1990) Proc. Natl.Acad. Sci. USA 87:2264-2268; Karlin, S., et al., (1993) Proc. Natl.Acad. Sci. USA 90:5873-5877; Dembo, A., et al., (1994) Ann. Prob.22:2022-2039; and Altschul, S. F. “Evaluating the statisticalsignificance of multiple distinct local alignments.” in Theoretical andComputational Methods in Genome Research (S. Suhai, ed.), (1997) pp.1-14, Plenum, New York.

With regards to the various aspects and preferred aspects of the CTLA4binders (e.g., ISVD such as a Nanobody) of the invention provided by theinvention, when it comes to the degree of sequence identity with respectto SEQ ID NO: 1 and/or the number and kind of “amino acid differences”that may be present in such a binder of the invention (i.e. compared tothe sequence of SEQ ID NO: 1), it should be noted that, when it is saidthat:

-   -   (i) an amino acid sequence of the invention has a degree of        sequence identity with the sequence of SEQ ID NO: 1 of at least        85%, preferably at least 90%, more preferably at least 95% (in        which the CDRs, any C-terminal extension that may be present, as        well as the mutations at positions 1, 11, 14, 45, 74, 83, 89,        96, 108, 110 and/or 112 required by the specific aspect        involved, are not taken into account for determining the degree        of sequence identity) when the comparison is performed by a        BLAST algorithm wherein the parameters of the algorithm are        selected to give the largest match between the respective        sequences over the entire length of the respective reference        sequences (e.g., expect threshold: 10; word size: 3; max matches        in a query range: 0; BLOSUM 62 matrix; gap costs: existence 11,        extension 1; conditional compositional score matrix adjustment);        and/or when it is said that:    -   (ii) an amino acid sequence of the invention has no more than 7,        preferably no more than 5, such as only 3, 2 or 1 “amino acid        differences” with the sequence of SEQ ID NO: 1 (again, not        taking into account any C-terminal extension that may be present        and not taking into account the mutations at positions 1, 11,        14, 45, 74, 83, 89, 96, 108, 110 and/or 112 required by the        specific aspect involved),        then this also includes sequences that have no amino acid        differences with the sequence of SEQ ID NO: 1 other than the        mutations at positions 1, 11, 14, 45, 74, 83, 89, 96, 108, 110        and/or 112 required by the specific aspect involved) and any        C-terminal extension that may be present.

Thus, in one specific aspect of the invention, the CTLA4 binders (e.g.,ISVD such as a Nanobody) of the invention comprises the amino acidsequence of SEQ ID NO: 1 but wherein at least 1 amino acid mutation atposition 1, 11, 14, 45, 74, 83, 89, 96, 108, 110 and/or 112 issubstituted (e.g., conservatively substituted) and may have 100%sequence identity with SEQ ID NO: 1 (including the CDRs, but not takinginto account the mutation(s) or combination of mutations at positions 1,11, 14, 45, 74, 83, 89, 96, 108, 110 and/or 112 disclosed herein and/orany C-terminal extension that may be present) and/or may have no aminoacid differences with SEQ ID NO: 1 (i.e., other than the mutation(s) orcombination of mutations at positions 1, 11, 14, 45, 74, 83, 89, 96,108, 110 and/or 112 disclosed herein and any C-terminal extension thatmay be present).

When any amino acid differences are present (i.e. besides any C-terminalextension and the mutations at positions 1, 11, 14, 45, 74, 83, 89, 96,108, 110 and/or 112 that are required by the specific aspect of theinvention involved), these amino acid differences may be present in theCDRs and/or in the framework regions, but they are preferably presentonly in the framework regions (as defined by the Abm convention, i.e.not in the CDRs as defined according to the Abm convention), i.e. suchthat the CTLA4 binders (e.g., ISVD such as a Nanobody) of the inventionhave the same CDRs (defined according to the Abm convention) as arepresent in SEQ ID NO: 1 or 60.

Also, when a CTLA4 binder (e.g., ISVD such as a Nanobody) of theinvention according to any aspect of the invention has one or more aminoacid differences with the sequence of SEQ ID NO: 1 (besides themutations at positions 1, 11, 14, 45, 74, 83, 89, 96, 108, 110 and/or112 that are required by the specific aspect involved), then somespecific, but non-limiting examples of such mutations/amino aciddifferences that may be present (i.e. compared to the sequences of SEQID NO: 1) are for example E1D, P41A, P41L, P41S or P41T (and inparticular P41A) and/or T87A (e.g., E1D (optional), L11V, A14P, Q45R,A74S, K83R, V89L, M96P and Q108L). Other examples of mutations are (asuitable combination of) one or more suitable “humanizing” substitutionssuch as Q108L; reference is for example made to WO 2009/138519 (or inthe prior art cited in WO 2009/138519) and WO 2008/020079 (or in theprior art cited in WO 2008/020079), as well as Tables A-3 to A-8 from WO2008/020079 (which are lists showing possible humanizing substitutions).Preferably, the CTLA4 binders of the invention contain at least a Q108Lhumanizing substitution.

Also, when the CTLA4 binders (e.g., ISVD such as a Nanobody) of theinvention are present at and/or form the N-terminal part of the CTLA4binder in which they are present, then they preferably contain a D atposition 1 (i.e. an E1D mutation compared to Reference A). Somepreferred but non-limiting examples of such N-terminal CTLA4 binders aregiven as SEQ ID NOs: 24 and 25 and 60. Accordingly, in a further aspect,the invention relates to a polypeptide of the invention (which is asfurther described herein) that has a CTLA4 binder of the invention(which is as further described herein) at its N-terminal end, whereinsaid CTLA4 binder of the invention has a D at position 1, and ispreferably chosen from the CTLA4 binders of SEQ ID NOs: 24 and 25 and60.

Similarly, when a CTLA4 binder (e.g., ISVD such as a Nanobody) of theinvention is used in monovalent format, it preferably has both aC-terminal extension X(n) as described herein and a D at position 1.Some preferred but non-limiting examples of such monovalent CTLA4binders are given as SEQ ID NOs: 42 and 43. Accordingly, in a furtheraspect, the invention relates to a monovalent CTLA4 binder of theinvention (which is as further described herein) that has a D atposition 1 and a C-terminal extension X(n) (which is preferably a singleAla residue). In one specific aspect, said monovalent CTLA4 binder ischosen from SEQ ID NOs: 42 or 43.

By means of preferred, but non-limiting, examples, SEQ ID NOs: 22-25 and40-42 and 60 are examples of CTLA4 binders (e.g., ISVD such as aNanobody) of the invention having further amino acid differences withSEQ ID NO: 1, i.e. A14P, Q45R, A74S, K83R and/or Q108L (in addition, asindicated in the previous paragraphs, SEQ ID NOs: 24, 25, 42 and 43 alsohave a E1D mutation). Thus, in a specific aspect, the invention relatesto CTLA4 binders of the invention (i.e. having mutations at positions11, 89, 110 and/or 112 as described herein and also further being asdescribed herein) that at least have a suitable combination of anoptional E1D mutation, A14P mutation, a Q45R mutation, an A74S mutation,a K83R mutation and a Q108L mutation, and preferably a suitablecombination of Q108L with any one of the other A14P, Q45R, A74S and K83Rmutations, and preferably in combination with any two of these othermutations, more preferably with any three of these mutations (such aswith the combination A14P, A74S and K83R or E1D, L11V, A14P, Q45R, A74S,K83R, V89L, M96P and Q108L), such as with all of these mutations (andagain, when the CTLA4 binder is monovalent or present at the N-terminalend of a CTLA4 binder of the invention, preferably also an E1Dmutation).

The CTLA4 binders (e.g., ISVD such as a Nanobody) of the invention, whenthey are used in a monovalent format and/or when a CTLA4 binding moietyis present at and/or forms the C-terminal end of the CTLA4 binder (orwhen they otherwise have an “exposed” C-terminal end in such apolypeptide, by which is generally meant that the C-terminal end of theISVD is not associated with or linked to a constant domain (such as aCH1 domain); reference is again made to WO 2012/175741 andPCT/EP2015/060643 (WO 2015/173325)), preferably also have a C-terminalextension of the formula (X)_(n), in which n is 1 to 10, preferably 1 to5, such as 1, 2, 3, 4 or 5 (and preferably 1 or 2, such as 1); and eachX is an (preferably naturally occurring) amino acid residue that isindependently chosen from naturally occurring amino acid residues(although according to preferred one aspect, it does not comprise anycysteine residues), and preferably independently chosen from the groupconsisting of alanine (A), glycine (G), valine (V), leucine (L) orisoleucine (I).

According to some preferred, but non-limiting examples of suchC-terminal extensions X_((n)), X and n can be as follows:

-   (a) n=1 and X=Ala;-   (b) n=2 and each X=Ala;-   (c) n=3 and each X=Ala;-   (d) n=2 and at least one X=Ala (with the remaining amino acid    residue(s) X being independently chosen from any naturally occurring    amino acid but preferably being independently chosen from Val, Leu    and/or Ile);-   (e) n=3 and at least one X=Ala (with the remaining amino acid    residue(s) X being independently chosen from any naturally occurring    amino acid but preferably being independently chosen from Val, Leu    and/or Ile);-   (f) n=3 and at least two X=Ala (with the remaining amino acid    residue(s) X being independently chosen from any naturally occurring    amino acid but preferably being independently chosen from Val, Leu    and/or Ile);-   (g) n=1 and X=Gly;-   (h) n=2 and each X=Gly;-   (i) n=3 and each X=Gly;-   (j) n=2 and at least one X=Gly (with the remaining amino acid    residue(s) X being independently chosen from any naturally occurring    amino acid but preferably being independently chosen from Val, Leu    and/or Ile);-   (k) n=3 and at least one X=Gly (with the remaining amino acid    residue(s) X being independently chosen from any naturally occurring    amino acid but preferably being independently chosen from Val, Leu    and/or Ile);-   (l) n=3 and at least two X=Gly (with the remaining amino acid    residue(s) X being independently chosen from any naturally occurring    amino acid but preferably being independently chosen from Val, Leu    and/or Ile);-   (m) n=2 and each X=Ala or Gly;-   (n) n=3 and each X=Ala or Gly;-   (o) n=3 and at least one X=Ala or Gly (with the remaining amino acid    residue(s) X being independently chosen from any naturally occurring    amino acid but preferably being independently chosen from Val, Leu    and/or Ile); or-   (p) n=3 and at least two X=Ala or Gly (with the remaining amino acid    residue(s) X being independently chosen from any naturally occurring    amino acid but preferably being independently chosen from Val, Leu    and/or Ile);    with aspects (a), (b), (c), (g), (h), (i), (m) and (n) being    particularly preferred, with aspects in which n=1 or 2 being    preferred and aspects in which n=1 being particularly preferred.

It should also be noted that, preferably, any C-terminal extensionpresent in a CTLA4 binder (e.g., ISVD such as a Nanobody) of theinvention does not contain a (free) cysteine residue unless saidcysteine residue is used or intended for further functionalization, forexample for PEGylation.

Some specific, but non-limiting examples of useful C-terminal extensionsare the following amino acid sequences: A, AA, AAA, G, GG, GGG, AG, GA,AAG, AGG, AGA, GGA, GAA or GAG.

When the CTLA4 binders (e.g., ISVD such as a Nanobody) of the inventioncontain mutations at positions 110 or 112 (optionally in combinationwith mutations at position 1, 11, 14, 45, 74, 83, 89, 96 and/or 108 asdescribed herein) (relative to the amino acid sequence of SEQ ID NO: 1),the C-terminal amino acid residues of framework 4 (starting fromposition 109) can, in an embodiment of the invention, be as set forth inSEQ ID NO: 1 but wherein the 5 C-terminal residues can be substituted asfollows:

-   -   (i) if no C-terminal extension is present: VTVKS (SEQ ID NO:        45), VTVQS (SEQ ID NO: 46), VKVSS (SEQ ID NO: 47) or VQVSS (SEQ        ID NO: 48); or    -   (ii) if a C-terminal extension is present: VTVKSX(n) (SEQ ID NO:        49), VTVQSX(n) (SEQ ID NO: 50), VKVSSX(n) (SEQ ID NO: 51) or        VQVSSX(n) (SEQ ID NO: 52), such as VTVKSA (SEQ ID NO: 53),        VTVQSA (SEQ ID NO: 54), VKVSSA (SEQ ID NO: 55) or VQVSSA (SEQ ID        NO: 56).

When the CTLA4 binders (e.g., ISVD such as a Nanobody) of the inventiondo not contain mutations at positions 110 or 112 (but only mutations atposition 1, 11, 14, 45, 74, 83, 89, 96 and/or 108 as described herein),the C-terminal amino acid residues of framework 4 (starting fromposition 109) can, in an embodiment of the invention, be as set forth inSEQ ID NO: 1 but wherein the 5 C-terminal residues can be substituted asfollows:

-   -   (i) when no C-terminal extension is present: VTVSS (SEQ ID        NO: 57) (as in the sequence of SEQ ID NO: 1); or    -   (ii) when a C-terminal extension is present: VTVSSX(n) (SEQ ID        NO: 58) such as VTVSSA (SEQ ID NO: 59). In these C-terminal        sequences, X and n are as defined herein for the C-terminal        extensions.

Some preferred but non-limiting examples of CTLA4 binders (e.g., ISVDsuch as a Nanobody) of the invention are given in SEQ ID NOs: 9-43 and60, and each of these sequences forms a further aspect of the invention(as do proteins, CTLA4 binders, polypeptides or other compounds orconstructs that comprise one of these sequences). Of these, the CTLA4binders of SEQ ID NOs: 9-25 and 60 do not have a C-terminal extension,and the CTLA4 binders of SEQ ID NOs: 26-43 contain a C-terminal alanine(which is a preferred but non-limiting example of a C-terminal extensionas described herein).

Examples of CTLA4 binders (e.g., ISVD such as a Nanobody) of theinvention comprise the amino acid sequences of SEQ ID NOs: 22, 23, 24,25, 40, 41, 42, 43 and 60.

Thus, in a first aspect, the invention relates to a CTLA4 binder (e.g.,an immunoglobulin single variable domain such as a Nanobody) having:

-   -   a CDR1 (according to Kabat) that is the amino acid sequence        FYGMG (SEQ ID NO: 2); and    -   a CDR2 (according to Kabat) that is the amino acid sequence        DIRTSAGRTYYADSVKG (SEQ ID NO: 3); and    -   a CDR3 (according to Kabat) that is the amino acid sequence        EPSGISGWDY (SEQ ID NO: 116);        and having:    -   a degree of sequence identity with the amino acid sequence of        SEQ ID NO: 1 of at least 85%, preferably at least 90%, more        preferably at least 95% (in which the CDRs, any C-terminal        extension that may be present, as well as the mutations at        positions 1, 11, 14, 45, 74, 83, 89, 96, 108, 110 and/or 112        required by the specific aspect involved are not taken into        account for determining the degree of sequence identity) when        the comparison is performed by a BLAST algorithm wherein the        parameters of the algorithm are selected to give the largest        match between the respective sequences over the entire length of        the respective reference sequences (e.g., expect threshold: 10;        word size: 3; max matches in a query range: 0; BLOSUM 62 matrix;        gap costs: existence 11, extension 1; conditional compositional        score matrix adjustment); and/or;        and/or    -   no more than 7, such as no more than 5, preferably no more than        3, such as only 3, 2 or 1 “amino acid differences” (as defined        herein, and not taking into account any of the above-listed        mutations at position(s) 1, 11, 14, 45, 74, 83, 89, 96, 108, 110        and/or 112 that may be present and not taking into account any        C-terminal extension that may be present) with the amino acid        sequence of SEQ ID NO: 1 (in which said amino acid differences,        if present, may be present in the frameworks and/or the CDRs but        are preferably present only in the frameworks and not in the        CDRs);        and optionally having:    -   a C-terminal extension (X)_(n), in which n is 1 to 10,        preferably 1 to 5, such as 1, 2, 3, 4 or 5 (and preferably 1 or        2, such as 1); and each X is an (preferably naturally occurring)        amino acid residue that is independently chosen, and preferably        independently chosen from the group consisting of alanine (A),        glycine (G), valine (V), leucine (L) or isoleucine (I);        wherein, in the amino acid sequence of the CTLA4 binder:    -   the amino acid residue at position 1 is preferably chosen from E        or D;    -   the amino acid residue at position 11 is preferably chosen from        L or V;    -   the amino acid residue at position 14 is preferably chosen from        A or P;    -   the amino acid residue at position 45 is preferably chosen from        Q or R;    -   the amino acid residue at position 74 is preferably chosen from        A or S;    -   the amino acid residue at position 83 is preferably chosen from        K or R;    -   the amino acid residue at position 89 is preferably suitably        chosen from T, V or L;    -   the amino acid residue at position 96 is preferably chosen from        M or P;    -   the amino acid residue at position 108 is preferably chosen from        Q or L;    -   the amino acid residue at position 110 is preferably suitably        chosen from T, K or Q; and/or    -   the amino acid residue at position 112 is preferably suitably        chosen from S, K or Q; such that, for example, one or more of        the following is true:    -   (i) position 1 is E or D;    -   (ii) position 11 is V;    -   (iii) position 14 is P;    -   (iv) position 45 is R;    -   (v) position 74 is S;    -   (vi) position 83 is R;    -   (vii) position 89 is T or L;    -   (viii) position 96 is P;    -   (ix) position 108 is L; and/or    -   for example, wherein the CTLA4 binder comprises one or more of        the sets of mutations below    -   a. position 11 is V and position 110 is K or Q;    -   b. position 11 is V and position 112 is K or Q.    -   c. position 89 is L and position 11 is V;    -   d. position 89 is L and position 110 is K or Q;    -   e. position 89 is L and position 112 is K or Q;    -   f. position 89 is L and position 11 is V and position 110 is K        or Q;    -   g. position 89 is L and position 11 is V and position 112 is K        or Q;    -   h. position 1 is E or D; position 11 is V; position 14 is P;        position 45 is R; position 74 is S; position 83 is R; position        89 is L; position 96 is P; and position 108 is L;    -   i. position 1 is E or D; position 11 is V; position 14 is P;        position 45 is R; position 74 is S; position 83 is R; position        89 is L; position 96 is P; position 108 is L; and position 110        is K or Q;    -   j. position 1 is E or D; position 11 is V; position 14 is P;        position 45 is R; position 74 is S; position 83 is R; position        89 is L; position 96 is P; position 108 is L; and position 112        is K or Q;    -   k. position 1 is E or D; position 11 is V; position 14 is P;        position 45 is R; position 74 is S; position 83 is R; position        89 is L; position 96 is P; and position 108 is L.

In a further aspect, the invention relates to a CTLA4 binder (e.g., animmunoglobulin single variable domain such as a Nanobody) having:

-   -   a CDR1 (according to Kabat) that is the amino acid sequence        FYGMG (SEQ ID NO: 2); and    -   a CDR2 (according to Kabat) that is the amino acid sequence        DIRTSAGRTYYADSVKG (SEQ ID NO: 3); and    -   a CDR3 (according to Kabat) that is the amino acid sequence        EPSGISGWDY (SEQ ID NO: 116.        and having:    -   a degree of sequence identity with the amino acid sequence of        SEQ ID NO: 1 of at least 85%, preferably at least 90%, more        preferably at least 95% (in which the CDRs, any C-terminal        extension that may be present, as well as the mutations at        positions 1, 11, 14, 45, 74, 83, 89, 96, 108, 110 and/or 112        required by the specific aspect involved are not taken into        account for determining the degree of sequence identity) when        the comparison is performed by a BLAST algorithm wherein the        parameters of the algorithm are selected to give the largest        match between the respective sequences over the entire length of        the respective reference sequences (e.g., expect threshold: 10;        word size: 3; max matches in a query range: 0; BLOSUM 62 matrix;        gap costs: existence 11, extension 1; conditional compositional        score matrix adjustment);        and/or    -   no more than 7, such as no more than 5, preferably no more than        3, such as only 3, 2 or 1 “amino acid differences” (as defined        herein, and not taking into account any of the above-listed        mutations at position(s) 1, 11, 14, 45, 74, 83, 89, 96, 108, 110        and/or 112 that may be present and not taking into account any        C-terminal extension that may be present) with the amino acid        sequence of SEQ ID NO: 1 (in which said amino acid differences,        if present, may be present in the frameworks and/or the CDRs but        are preferably present only in the frameworks and not in the        CDRs);        and optionally having:    -   a C-terminal extension (X)_(n), in which n is 1 to 10,        preferably 1 to 5, such as 1, 2, 3, 4 or 5 (and preferably 1 or        2, such as 1); and each X is an (preferably naturally occurring)        amino acid residue that is independently chosen, and preferably        independently chosen from the group consisting of alanine (A),        glycine (G), valine (V), leucine (L) or isoleucine (I);        which CTLA4 binder (e.g., an immunoglobulin single variable        domain such as a Nanobody) comprises one or more of the        following amino acid residues (i.e. mutations compared to the        amino acid sequence of SEQ ID NO: 1) at the positions mentioned        (numbering according to Kabat):    -   1D or 1E;    -   11V;    -   14P;    -   45R;    -   74S;    -   83R;    -   89T or 89L;    -   96P; or    -   108L;        for example, wherein the CTLA4 binder comprises one or more of        the sets of mutations below:    -   1D or 1E in combination with 11V; 14P; 45R; 74S; 83R; 89L; 96P;        and 108L;    -   11V in combination with 110K or 110Q;    -   11V in combination with 112K or 112Q;    -   89L in combination with 11V;    -   89L in combination with 110K or 110Q;    -   89L in combination with 112K or 112Q;    -   1D or 1E in combination with 11V; 14P; 45R; 74S; 83R; 89L; 96P;        108L and 110K or 110Q;    -   1D or 1E in combination with 11V; 14P; 45R; 74S; 83R; 89L; 96P;        108L and 112K or 112Q;    -   89L in combination with 11V and 110K or 110Q; or    -   89L in combination with 11V and 112K or 112Q;

As mentioned, when a CTLA4 binder (e.g., ISVD such as a Nanobody) of theinvention is used in a monovalent format and/or wherein the CTLA4binding moiety is present at the C-terminal end of a CTLA4 binder of theinvention (as defined herein), the CTLA4 binder preferably has aC-terminal extension X(n), which C-terminal extension may be asdescribed herein for the CTLA4 binders of the invention and/or asdescribed in WO 2012/175741 or PCT/EP2015/060643 (WO2015/173325).

Some preferred, but non-limiting examples of CTLA4 binders (e.g., ISVDsuch as a Nanobody) of the invention are given in SEQ ID NOs: 8-43 or60, and each of these amino acid sequences individually forms a furtheraspect of the invention.

As mentioned, in the invention, amino acid sequences in which position89 is T; or in which position 1 is E or D, position 11 is V, position 14is P, position 45 is R, position 74 is S, position 83 is R, position 89is L, position 96 is P and position 108 is L; or in which position 11 isV and position 89 is L (optionally in suitable combination with a 110Kor 110Q mutation and/or a 112K or 112Q mutation, and in particular incombination with a 110K or 110Q mutation) are particularly preferred.Even more preferred are amino acid sequences in which position 11 is Vand position 89 is L, optionally with a 110K or 110Q mutation.

Thus, in one preferred aspect, the invention relates to a CTLA4 binder(e.g., an immunoglobulin single variable domain such as a Nanobody)having:

-   -   a CDR1 (according to Kabat) that is the amino acid sequence        FYGMG (SEQ ID NO: 2); and    -   a CDR2 (according to Kabat) that is the amino acid sequence        DIRTSAGRTYYADSVKG (SEQ ID NO: 3); and    -   a CDR3 (according to Kabat) that is the amino acid sequence        EPSGISGWDY (SEQ ID NO: 116;        and having:    -   a degree of sequence identity with the amino acid sequence of        SEQ ID NO: 1 of at least 85%, preferably at least 90%, more        preferably at least 95% (in which the CDRs, any C-terminal        extension that may be present, as well as the mutations at        positions 1, 11, 14, 45, 74, 83, 89, 96, 108, 110 and/or 112        required by the specific aspect involved are not taken into        account for determining the degree of sequence identity), when        the comparison is performed by a BLAST algorithm wherein the        parameters of the algorithm are selected to give the largest        match between the respective sequences over the entire length of        the respective reference sequences (e.g., expect threshold: 10;        word size: 3; max matches in a query range: 0; BLOSUM 62 matrix;        gap costs: existence 11, extension 1; conditional compositional        score matrix adjustment); and/or;        and/or    -   no more than 7, such as no more than 5, preferably no more than        3, such as only 3, 2 or 1 “amino acid differences” (as defined        herein, and not taking into account any of the above-listed        mutations at position(s) 1, 11, 14, 45, 74, 83, 89, 96, 108, 110        and/or 112 that may be present and not taking into account any        C-terminal extension that may be present) with the amino acid        sequence of SEQ ID NO: 1 (in which said amino acid differences,        if present, may be present in the frameworks and/or the CDRs but        are preferably present only in the frameworks and not in the        CDRs);        and optionally having:    -   a C-terminal extension (X)_(n), in which n is 1 to 10,        preferably 1 to 5, such as 1, 2, 3, 4 or 5 (and preferably 1 or        2, such as 1); and each X is an (preferably naturally occurring)        amino acid residue that is independently chosen, and preferably        independently chosen from the group consisting of alanine (A),        glycine (G), valine (V), leucine (L) or isoleucine (I);        wherein, in the amino acid sequence of the CTLA4 binder:    -   the amino acid residue at position 1 is preferably chosen from E        or D;    -   the amino acid residue at position 11 is preferably chosen from        L or V;    -   the amino acid residue at position 14 is preferably chosen from        A or P;    -   the amino acid residue at position 45 is preferably chosen from        Q or R;    -   the amino acid residue at position 74 is preferably chosen from        A or S;    -   the amino acid residue at position 83 is preferably chosen from        K or R;    -   the amino acid residue at position 89 is preferably chosen from        T, L or V;    -   the amino acid residue at position 96 is preferably chosen from        M or P;    -   the amino acid residue at position 108 is preferably chosen from        L or Q;    -   the amino acid residue at position 110 is preferably suitably        chosen from T, K or Q (and is preferably T); and/or    -   the amino acid residue at position 112 is preferably suitably        chosen from S, K or Q (and is preferably S).

In another preferred aspect, the invention relates to a CTLA4 binder(e.g., an immunoglobulin single variable domain such as a Nanobody)having:

-   -   a CDR1 (according to Kabat) that is the amino acid sequence        FYGMG (SEQ ID NO: 2); and    -   a CDR2 (according to Kabat) that is the amino acid sequence        DIRTSAGRTYYADSVKG (SEQ ID NO: 3); and    -   a CDR3 (according to Kabat) that is the amino acid sequence        EPSGISGWDY (SEQ ID NO: 116;        and having:    -   a degree of sequence identity with the amino acid sequence of        SEQ ID NO: 1 of at least 85%, preferably at least 90%, more        preferably at least 95% (in which the CDRs, any C-terminal        extension that may be present, as well as the mutations at        positions 1, 11, 14, 45, 74, 83, 89, 96, 108, 110 and/or 112        required by the specific aspect involved are not taken into        account for determining the degree of sequence identity) when        the comparison is performed by a BLAST algorithm wherein the        parameters of the algorithm are selected to give the largest        match between the respective sequences over the entire length of        the respective reference sequences (e.g., expect threshold: 10;        word size: 3; max matches in a query range: 0; BLOSUM 62 matrix;        gap costs: existence 11, extension 1; conditional compositional        score matrix adjustment);        and/or    -   no more than 7, such as no more than 5, preferably no more than        3, such as only 3, 2 or 1 “amino acid differences” (as defined        herein, and not taking into account any of the above-listed        mutations at position(s) 1, 11, 14, 45, 74, 83, 89, 96, 108, 110        and/or 112 that may be present and not taking into account any        C-terminal extension that may be present) with the amino acid        sequence of SEQ ID NO: 1 (in which said amino acid differences,        if present, may be present in the frameworks and/or the CDRs but        are preferably present only in the frameworks and not in the        CDRs);        and optionally having:    -   a C-terminal extension (X)_(n), in which n is 1 to 10,        preferably 1 to 5, such as 1, 2, 3, 4 or 5 (and preferably 1 or        2, such as 1); and each X is an (preferably naturally occurring)        amino acid residue that is independently chosen, and preferably        independently chosen from the group consisting of alanine (A),        glycine (G), valine (V), leucine (L) or isoleucine (I);        in which, for example, the CTLA4 binder comprises one or more        mutations according to the following:    -   the amino acid residue at position 1 is E or D;    -   the amino acid residue at position 11 is V;    -   the amino acid residue at position 14 is P;    -   the amino acid residue at position 45 is R;    -   the amino acid residue at position 74 is S;    -   the amino acid residue at position 83 is R;    -   the amino acid residue at position 89 is L;    -   the amino acid residue at position 96 is P;    -   the amino acid residue at position 108 is L;    -   the amino acid residue at position 110 is preferably chosen from        T, K or Q; or    -   the amino acid residue at position 112 is preferably chosen from        S, K or Q.

In one specific, but non-limiting aspect, the CTLA4 binders (e.g., ISVDsuch as a Nanobody) of the invention comprise the one or more offollowing sets of mutations (i.e. mutations compared to the sequence ofSEQ ID NO: 1) at the positions mentioned (numbering according to Kabat):

-   -   11V in combination with 89L;    -   11V in combination with 110K or 110Q;    -   11V in combination with 112K or 112Q;    -   11V in combination with 89L and 110K or 110Q;    -   11V in combination with 89L and 112K or 112Q;    -   11V in combination with 1D or 1E, 14P, 45R, 74S, 83R, 89L, 96P,        108L and 110K or 110Q;    -   11V in combination with 1D or 1E, 14P, 45R, 74S, 83R, 89L, 96P,        108L and 112K or 112Q; or    -   11V in combination with 1D or 1E, 14P, 45R, 74S, 83R, 89L, 96P        and 108L.        and have CDRs which are in a CTLA4 binder of Table A, e.g., in        SEQ ID NO: 1 or SEQ ID NO: 60 (e.g., according to Kabat) and        have an overall degree of sequence identity with the amino acid        sequence of SEQ ID NO: 1 that are as described herein.

In another specific, but non-limiting aspect, the CTLA4 binders (e.g.,ISVD such as a Nanobody) of the invention comprise one or more of thefollowing sets of mutations (i.e. mutations compared to the sequence ofSEQ ID NO: 1) at the positions mentioned (numbering according to Kabat):

-   -   89L in combination with 11V;    -   89L in combination with 110K or 110Q;    -   89L in combination with 112K or 112Q;    -   89L in combination with 11V and 110K or 110Q;    -   89L in combination with 11V and 112K or 112Q;    -   89L in combination with 1D or 1E, 11V, 14P, 45R, 74S, 83R, 96P        and 108L;    -   89L in combination with 1D or 1E, 11V, 14P, 45R, 74S, 83R, 96P,        108L and 110K or 110Q; or    -   89L in combination with 1D or 1E, 11V, 14P, 45R, 74S, 83R, 96P,        108L and 112K or 112Q,        and have CDRs which are in a CTLA4 binder of Table A, e.g., in        SEQ ID NO: 1 or SEQ ID NO: 60 (e.g., according to Kabat) and        have an overall degree of sequence identity with the amino acid        sequence of SEQ ID NO: 1 that are as described herein.

In another specific, but non-limiting aspect, the CTLA4 binders (e.g.,ISVD such as a Nanobody) of the invention comprise one or more of thefollowing amino acid sets of mutations (i.e. mutations compared to thesequence of SEQ ID NO: 1) at the positions mentioned (numberingaccording to Kabat):

-   -   110K or 110Q in combination with 11V;    -   110K or 110Q in combination with 89L;    -   110K or 110Q in combination with 11V and 89L;    -   110K or 110Q in combination with 1D or 1E, 11V, 14P, 45R, 74S,        83R, 89L, 96P and 108L.        and have CDRs which are in a CTLA4 binder of Table A, e.g., in        SEQ ID NO: 1 or SEQ ID NO: 60 (e.g., according to Kabat) and        have an overall degree of sequence identity with the amino acid        sequence of SEQ ID NO: 1 that are as described herein.

In another specific, but non-limiting aspect, the CTLA4 binders (e.g.,ISVD such as a Nanobody) of the invention comprise one or more of thefollowing sets of mutations (i.e. mutations compared to the sequence ofSEQ ID NO: 1) at the positions mentioned (numbering according to Kabat):

-   -   112K or 112Q in combination with 11V;    -   112K or 112Q in combination with 89L; or    -   112K or 112Q in combination with 11V and 89L; or    -   112K or 112Q in combination with 1D or 1E, 11V, 14P, 45R, 74S,        83R, 89L, 96P and 108L.        and have CDRs which are in a CTLA4 binder of Table A, e.g., in        SEQ ID NO: 1 or SEQ ID NO: 60 (e.g., according to Kabat) and        have an overall degree of sequence identity with the amino acid        sequence of SEQ ID NO: 1 that are as described herein.

In another aspect, the CTLA4 binders (e.g., ISVD such as a Nanobody) ofthe invention comprise a T at position 89 and have CDRs such as thoseset forth in SEQ ID NO: 60 (e.g., according to Kabat) and have anoverall degree of sequence identity with the amino acid sequence of SEQID NO: 1 that are as described herein.

In another aspect, the CTLA4 binders (e.g., ISVD such as a Nanobody) ofthe invention comprise a V at position 11 and an L at position 89 andhave CDRs such as those set forth in SEQ ID NO: 1 or 60 (e.g., accordingto Kabat) and have an overall degree of sequence identity with the aminoacid sequence of SEQ ID NO: 1 that are as described herein.

As mentioned, the CTLA4 binders (e.g., ISVD such as a Nanobody) of theinvention according to the above aspects preferably further contain asuitable combination of an E1D mutation, L11V mutation, A14P mutation, aQ45R mutation, an A74S mutation, a K83R mutation, a V89L mutation, anM96P mutation and a Q108L mutation, and, in an embodiment of theinvention, a suitable combination of Q108L with any one of the otherA14P, Q45R, A74S and K83R mutations, and, in an embodiment of theinvention, in combination with any two of these other mutations, morepreferably with any three of these mutations (such as with thecombination A14P, A74S and K83R), such as with all four of thesemutations (and again, when the CTLA4 binder is monovalent or present atthe N-terminal end of a CTLA4 binder of the invention, preferably alsoan E1D mutation).

In another aspect, the invention relates to a CTLA4 binder (e.g., animmunoglobulin single variable domain such as a Nanobody) having:

-   -   a CDR1 (according to Abm) that is the amino acid sequence        GGTFSFYGMG (SEQ ID NO: 5); and    -   a CDR2 (according to Abm) that is the amino acid sequence        DIRTSAGRTY (SEQ ID NO: 6); and    -   a CDR3 (according to Abm) that is the amino acid sequence        EPSGISGWDY (SEQ ID NO: 116;        and having:    -   a degree of sequence identity with the amino acid sequence of        SEQ ID NO: 1 of at least 85%, preferably at least 90%, more        preferably at least 95% (in which the CDRs, any C-terminal        extension that may be present, as well as the mutations at        positions 1, 11, 14, 45, 74, 83, 89, 96, 108, 110 and/or 112        required by the specific aspect involved are not taken into        account for determining the degree of sequence identity) when        the comparison is performed by a BLAST algorithm wherein the        parameters of the algorithm are selected to give the largest        match between the respective sequences over the entire length of        the respective reference sequences (e.g., expect threshold: 10;        word size: 3; max matches in a query range: 0; BLOSUM 62 matrix;        gap costs: existence 11, extension 1; conditional compositional        score matrix adjustment);        and/or    -   no more than 7, such as no more than 5, preferably no more than        3, such as only 3, 2 or 1 “amino acid differences” (as defined        herein, and not taking into account any of the above-listed        mutations at position(s) 1, 11, 14, 45, 74, 83, 89, 96, 108, 110        and/or 112 that may be present and not taking into account any        C-terminal extension that may be present) with the amino acid        sequence of SEQ ID NO: 1 (in which said amino acid differences,        if present, may be present in the frameworks and/or the CDRs but        are preferably present only in the frameworks and not in the        CDRs);        and optionally having:    -   a C-terminal extension (X)_(n), in which n is 1 to 10,        preferably 1 to 5, such as 1, 2, 3, 4 or 5 (and preferably 1 or        2, such as 1); and each X is an (preferably naturally occurring)        amino acid residue that is independently chosen, and preferably        independently chosen from the group consisting of alanine (A),        glycine (G), valine (V), leucine (L) or isoleucine (I);        comprising an amino acid sequence wherein:    -   the amino acid residue at position 1 is E or D;    -   the amino acid residue at position 11 is L or V;    -   the amino acid residue at position 14 is P;    -   the amino acid residue at position 45 is R;    -   the amino acid residue at position 74 is S;    -   the amino acid residue at position 83 is R;    -   the amino acid residue at position 89 is preferably chosen from        T, V or L;    -   the amino acid residue at position 96 is P;    -   the amino acid residue at position 108 is L;    -   the amino acid residue at position 110 is preferably chosen from        T, K or Q; and    -   the amino acid residue at position 112 is preferably chosen from        S, K or Q; for example, such that one or more of the following        is true:    -   (i) position 1 is D or E;    -   (ii) position 11 is V;    -   (iii) position 14 is P;    -   (iv) position 45 is R;    -   (v) position 74 is S;    -   (vi) position 83 is R;    -   (vii) position 89 is L or T;    -   (viii) position 96 is P; or    -   (ix) position 108 is L.        for example, wherein the CTLA4 binder comprises one or more of        the sets of mutations below:    -   a. position 11 is V and position 110 is K or Q;    -   b. position 11 is V and position 112 is K or Q;    -   c. position 89 is L and position 11 is V;    -   d. position 89 is L and position 110 is K or Q;    -   e. position 89 is L and position 112 is K or Q;    -   f. position 89 is L and position 11 is V and position 110 is K        or Q; or    -   g. position 89 is L and position 11 is V and position 112 is K        or Q.

In a further aspect, the invention relates to an CTLA4 binder (e.g., animmunoglobulin single variable domain such as a Nanobody) having:

-   -   a CDR1 (according to Abm) that is the amino acid sequence        GGTFSFYGMG (SEQ ID NO: 5); and    -   a CDR2 (according to Abm) that is the amino acid sequence        DIRTSAGRTY (SEQ ID NO: 6); and    -   a CDR3 (according to Abm) that is the amino acid sequence        EPSGISGWDY (SEQ ID NO: 116;        and having:    -   a degree of sequence identity with the amino acid sequence of        SEQ ID NO: 1 of at least 85%, preferably at least 90%, more        preferably at least 95% (in which the CDRs, any C-terminal        extension that may be present, as well as the mutations at        positions 1, 11, 14, 45, 74, 83, 89, 96, 108, 110 and/or 112        required by the specific aspect involved are not taken into        account for determining the degree of sequence identity) when        the comparison is performed by a BLAST algorithm wherein the        parameters of the algorithm are selected to give the largest        match between the respective sequences over the entire length of        the respective reference sequences (e.g., expect threshold: 10;        word size: 3; max matches in a query range: 0; BLOSUM 62 matrix;        gap costs: existence 11, extension 1; conditional compositional        score matrix adjustment);        and/or    -   no more than 7, such as no more than 5, preferably no more than        3, such as only 3, 2 or 1 “amino acid differences” (as defined        herein, and not taking into account any of the above-listed        mutations at position(s) 1, 11, 14, 45, 74, 83, 89, 96, 108, 110        and/or 112 that may be present and not taking into account any        C-terminal extension that may be present) with the amino acid        sequence of SEQ ID NO: 1 (in which said amino acid differences,        if present, may be present in the frameworks and/or the CDRs but        are preferably present only in the frameworks and not in the        CDRs);        and optionally having:    -   a C-terminal extension (X)_(n), in which n is 1 to 10,        preferably 1 to 5, such as 1, 2, 3, 4 or 5 (and preferably 1 or        2, such as 1); and each X is an (preferably naturally occurring)        amino acid residue that is independently chosen, and preferably        independently chosen from the group consisting of alanine (A),        glycine (G), valine (V), leucine (L) or isoleucine (I);        which CTLA4 binder (e.g., an immunoglobulin single variable        domain such as a Nanobody) comprises one or more of the        following amino acid residues (i.e. mutations compared to the        amino acid sequence of SEQ ID NO: 1) at the positions mentioned        (numbering according to Kabat):    -   1D or 1E;    -   11V;    -   14P;    -   45R;    -   74S;    -   83R;    -   89L or 89T;    -   96P; or    -   108L;        for example, wherein the CTLA4 binder comprises one or more of        the sets of mutations below:    -   11V in combination with 110K or 110Q;    -   11V in combination with 112K or 112Q;    -   89L in combination with 11V;    -   89L in combination with 110K or 110Q;    -   89L in combination with 112K or 112Q;    -   89L in combination with 11V and 110K or 110Q; or    -   89L in combination with 11V and 112K or 112Q.

As mentioned, when a CTLA4 binder (e.g., ISVD such as a Nanobody) of theinvention is used in a monovalent format and/or wherein the CTLA4binding moiety is present at the C-terminal end of a CTLA4 binder of theinvention (as defined herein), the CTLA4 binder preferably has aC-terminal extension X(n), which C-terminal extension may be asdescribed herein for the CTLA4 binders of the invention and/or asdescribed in WO 2012/175741 or PCT/EP2015/060643 (WO2015/173325).

Some preferred, but non-limiting examples of CTLA4 binders (e.g., ISVDsuch as a Nanobody) of the invention are given in SEQ ID NOs: 8-43 and60, and each of these amino acid sequences individually forms a furtheraspect of the invention.

As mentioned, in the invention, amino acid sequences in which position89 is T; or in which position 1 is E or D, position 11 is V, position 14is P, position 45 is R, position 74 is S, position 83 is R, position 89is L, position 96 is P, or position 108 is L; or in which position 11 isV and position 89 is L (optionally in suitable combination with a 110Kor 110Q mutation and/or a 112K or 112Q mutation, and in particular incombination with a 110K or 110Q mutation) are particularly preferred.Even more preferred are amino acid sequences in which position 11 is Vand position 89 is L, optionally with a 110K or 110Q mutation.

Thus, in one preferred aspect, the invention relates to a CTLA4 binder(e.g., an immunoglobulin single variable domain such as a Nanobody)having:

-   -   a CDR1 (according to Abm) that is the amino acid sequence        GGTFSFYGMG (SEQ ID NO: 5); and    -   a CDR2 (according to Abm) that is the amino acid sequence        DIRTSAGRTY (SEQ ID NO: 6); and    -   a CDR3 (according to Abm) that is the amino acid sequence        EPSGISGWDY (SEQ ID NO: 116;        and having:    -   a degree of sequence identity with the amino acid sequence of        SEQ ID NO: 1 of at least 85%, preferably at least 90%, more        preferably at least 95% (in which the CDRs, any C-terminal        extension that may be present, as well as the mutations at        positions 1, 11, 14, 45, 74, 83, 89, 96, 108, 110 and/or 112        required by the specific aspect involved are not taken into        account for determining the degree of sequence identity) when        the comparison is performed by a BLAST algorithm wherein the        parameters of the algorithm are selected to give the largest        match between the respective sequences over the entire length of        the respective reference sequences (e.g., expect threshold: 10;        word size: 3; max matches in a query range: 0; BLOSUM 62 matrix;        gap costs: existence 11, extension 1; conditional compositional        score matrix adjustment);        and/or    -   no more than 7, such as no more than 5, preferably no more than        3, such as only 3, 2 or 1 “amino acid differences” (as defined        herein, and not taking into account any of the above-listed        mutations at position(s) 1, 11, 14, 45, 74, 83, 89, 96, 108, 110        and/or 112 that may be present and not taking into account any        C-terminal extension that may be present) with the amino acid        sequence of SEQ ID NO: 1 (in which said amino acid differences,        if present, may be present in the frameworks and/or the CDRs but        are preferably present only in the frameworks and not in the        CDRs);        and optionally having:    -   a C-terminal extension (X)_(n), in which n is 1 to 10,        preferably 1 to 5, such as 1, 2, 3, 4 or 5 (and preferably 1 or        2, such as 1); and each X is an (preferably naturally occurring)        amino acid residue that is independently chosen, and preferably        independently chosen from the group consisting of alanine (A),        glycine (G), valine (V), leucine (L) or isoleucine (I);        comprising an amino acid sequence having one or mutations        (relative to the amino acid sequence of SEQ ID NO: 1) according        to the following:    -   the amino acid residue at position 1 is preferably chosen from E        and D;    -   the amino acid residue at position 11 is preferably chosen from        L and V;    -   the amino acid residue at position 14 is preferably chosen from        A and P;    -   the amino acid residue at position 45 is preferably chosen from        Q and R;    -   the amino acid residue at position 74 is preferably chosen from        A and S;    -   the amino acid residue at position 83 is preferably chosen from        K and R;    -   the amino acid residue at position 89 is preferably chosen from        T, L and V;    -   the amino acid residue at position 96 is preferably chosen from        M or P;    -   the amino acid residue at position 108 is preferably chosen from        L or Q;    -   the amino acid residue at position 110 is preferably chosen from        T, K or Q (and is preferably T); and    -   the amino acid residue at position 112 is preferably chosen from        S, K or Q (and in preferably S).

In another preferred aspect, the invention relates to a CTLA4 binder(e.g., an immunoglobulin single variable domain such as a Nanobody)having:

-   -   a CDR1 (according to Abm) that is the amino acid sequence        GGTFSFYGMG (SEQ ID NO: 5); and    -   a CDR2 (according to Abm) that is the amino acid sequence        DIRTSAGRTY (SEQ ID NO: 6); and    -   a CDR3 (according to Abm) that is the amino acid sequence        EPSGISGWDY (SEQ ID NO: 116;        and having:    -   a degree of sequence identity with the amino acid sequence of        SEQ ID NO: 1 of at least 85%, preferably at least 90%, more        preferably at least 95% (in which the CDRs, any C-terminal        extension that may be present, as well as the mutations at        positions 1, 11, 14, 45, 74, 83, 89, 96, 108, 110 and/or 112        required by the specific aspect involved are not taken into        account for determining the degree of sequence identity) when        the comparison is performed by a BLAST algorithm wherein the        parameters of the algorithm are selected to give the largest        match between the respective sequences over the entire length of        the respective reference sequences (e.g., expect threshold: 10;        word size: 3; max matches in a query range: 0; BLOSUM 62 matrix;        gap costs: existence 11, extension 1; conditional compositional        score matrix adjustment);        and/or    -   no more than 7, such as no more than 5, preferably no more than        3, such as only 3, 2 or 1 “amino acid differences” (as defined        herein, and not taking into account any of the above-listed        mutations at position(s) 1, 11, 14, 45, 74, 83, 89, 96, 108, 110        and/or 112 that may be present and not taking into account any        C-terminal extension that may be present) with the amino acid        sequence of SEQ ID NO: 1 (in which said amino acid differences,        if present, may be present in the frameworks and/or the CDRs but        are preferably present only in the frameworks and not in the        CDRs);        and optionally having:    -   a C-terminal extension (X)_(n), in which n is 1 to 10,        preferably 1 to 5, such as 1, 2, 3, 4 or 5 (and preferably 1 or        2, such as 1); and each X is an (preferably naturally occurring)        amino acid residue that is independently chosen, and preferably        independently chosen from the group consisting of alanine (A),        glycine (G), valine (V), leucine (L) or isoleucine (I);        in which the CTLA4 binder comprises one or more of the following        mutations:    -   the amino acid residue at position 1 is D or E;    -   the amino acid residue at position 11 is V;    -   the amino acid residue at position 14 is P;    -   the amino acid residue at position 45 is R;    -   the amino acid residue at position 74 is S;    -   the amino acid residue at position 83 is R;    -   the amino acid residue at position 89 is L;    -   the amino acid residue at position 96 is P;    -   the amino acid residue at position 108 is L;    -   the amino acid residue at position 110 is preferably suitably        chosen from T, K or Q; or    -   the amino acid residue at position 112 is preferably suitably        chosen from S, K or Q.

In one specific, but non-limiting aspect, the CTLA4 binders (e.g., ISVDsuch as a Nanobody) of the invention comprise the one or more offollowing sets of mutations (i.e. mutations compared to the sequence ofSEQ ID NO: 1) at the positions mentioned (numbering according to Kabat):

-   -   11V in combination with 89L;    -   11V in combination with 1D, 14P, 45R, 74S, 83R, 89L, 96P, 108L;    -   11V in combination with 1E, 14P, 45R, 74S, 83R, 89L, 96P, 108L;    -   11V in combination with 110K or 110Q;    -   11V in combination with 110K or 110Q, and 1D or 1E and 14P, 45R,        74S, 83R, 89L, 96P, and 108L;    -   11V in combination with 112K or 112Q;    -   11V in combination with 112K or 112Q, and 1D or 1E and 14P, 45R,        74S, 83R, 89L, 96P, and 108L;    -   11V in combination with 89L and 110K or 110Q; or    -   11V in combination with 89L and 112K or 112Q, and have CDRs        which are in a CTLA4 binder of Table A, e.g., in SEQ ID NO: 1 or        SEQ ID NO: 60 (e.g., according to Abm) and have an overall        degree of sequence identity with the amino acid sequence of SEQ        ID NO: 1 that are as described herein.

In another specific, but non-limiting aspect, the CTLA4 binders (e.g.,ISVD such as a Nanobody) of the invention comprise the following sets ofmutations (i.e. mutations compared to the sequence of SEQ ID NO: 1) atthe positions mentioned (numbering according to Kabat):

-   -   89L in combination with 11V;    -   89L in combination with 1D or 1E, 11V, 14P, 45R, 74S, 83R, 96P        and 108L;    -   89L in combination with 110K or 110Q;    -   89L in combination with 110K or 110Q and 1D or 1E and 11V, 14P,        45R, 74S, 83R, 96P and 108L;    -   89L in combination with 112K or 112Q;    -   89L in combination with 112K or 112Q and 1D or 1E and 11V, 14P,        45R, 74S, 83R, 96P and 108L;    -   89L in combination with 11V and 110K or 110Q; or    -   89L in combination with 11V and 112K or 112Q;        and have CDRs which are in a CTLA4 binder of Table A, e.g., in        SEQ ID NO: 1 or SEQ ID NO: 60 (e.g., according to Abm) and have        an overall degree of sequence identity with the amino acid        sequence of SEQ ID NO: 1 that are as described herein.

In another specific, but non-limiting aspect, the CTLA4 binders (e.g.,ISVD such as a Nanobody) of the invention comprise the following sets ofmutations (i.e. mutations compared to the sequence of SEQ ID NO: 1) atthe positions mentioned (numbering according to Kabat):

-   -   110K or 110Q in combination with 11V;    -   110K or 110Q in combination with 89L;    -   110K or 110Q in combination with 11V and 89L; or    -   110K or 110Q in combination with 1D or 1E and 11V, 14P, 45R,        74S, 83R, 89L, 96P and 108L,        and have CDRs which are in a CTLA4 binder of Table A, e.g., in        SEQ ID NO: 1 or SEQ ID NO: 60 (e.g., according to Abm) and have        an overall degree of sequence identity with the amino acid        sequence of SEQ ID NO: 1 that are as described herein.

In another specific, but non-limiting aspect, the CTLA4 binders (e.g.,ISVD such as a Nanobody) of the invention comprise the following sets ofmutations (i.e. mutations compared to the sequence of SEQ ID NO: 1) atthe positions mentioned (numbering according to Kabat):

-   -   112K or 112Q in combination with 11V;    -   112K or 112Q in combination with 89L;    -   112K or 112Q in combination with 11V and 89L; or    -   112K or 112Q in combination with 1D or 1E and 11V, 14P, 45R,        74S, 83R, 89L, 96P and 108L,        and have CDRs which are in a CTLA4 binder of Table A, e.g., in        SEQ ID NO: 1 or SEQ ID NO: 60 (e.g., according to Abm) and have        an overall degree of sequence identity with the amino acid        sequence of SEQ ID NO: 1 that are as described herein.

In another aspect, the CTLA4 binders (e.g., ISVD such as a Nanobody) ofthe invention comprise a T at position 89 and have CDRs such as thoseset forth in SEQ ID NO: 1 or 60 (e.g., according to Abm) and have anoverall degree of sequence identity with the amino acid sequence of SEQID NO: 1 that are as described herein.

In another aspect, the CTLA4 binders (e.g., ISVD such as a Nanobody) ofthe invention comprise a V at position 11 and an L at position 89 andhave CDRs such as those set forth in SEQ ID NO: 60 (e.g., according toAbm) and have an overall degree of sequence identity with the amino acidsequence of SEQ ID NO: 1 that are as described herein.

As mentioned, the CTLA4 binders (e.g., ISVD such as a Nanobody) of theinvention according to the above aspects are preferably further suchthat they contain a suitable combination of an optional E1D mutation, anL11V mutation, A14P mutation, a Q45R mutation, an A74S mutation, a K83Rmutation, a V89L mutation, an M96P mutation and a Q108L mutation, andpreferably a suitable combination of Q108L with any one of the otherA14P, Q45R, A74S and K83R mutations, and preferably in combination withany two of these other mutations, more preferably with any three ofthese mutations (such as with the combination A14P, A74S and K83R), suchas with all of these mutations (and again, when the CTLA4 binder ismonovalent or present at the N-terminal end of a CTLA4 binder of theinvention, preferably also an E1D mutation). In an embodiment of theinvention, the CTLA4 binders of the present invention comprise themutations E1D (or lacking such a mutation, wherein residue 1 is E),L11V, A14P, Q45R, A74S, K83R, V89L, M96P, Q108L.

In another specific, but non-limiting aspect, the invention relates to aCTLA4 binder (e.g., an immunoglobulin single variable domain such as aNanobody) that is or essentially consists of an amino acid sequencechosen from one of the following amino acid sequences: SEQ ID NO: 8, SEQID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13,SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO:18, SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21, SEQ ID NO: 22, SEQ IDNO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27, SEQID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, SEQ ID NO: 32,SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO:37, SEQ ID NO: 38, SEQ ID NO: 39, SEQ ID NO: 40, SEQ ID NO: 41, SEQ IDNO: 42, SEQ ID NO: 43 or SEQ ID NO: 60.

In another specific, but non-limiting aspect, the invention relates to aCTLA4 binder (e.g., an immunoglobulin single variable domain such as aNanobody) that is or essentially consists of an amino acid sequencechosen from one of the following amino acid sequences: SEQ ID NO: 22,SEQ ID NO: 23, SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 40, SEQ ID NO:41, SEQ ID NO: 42, SEQ ID NO: 43 or SEQ ID NO: 60.

Also, as already indicated herein, the amino acid residues of a CTLA4binder (e.g., an ISVD such as a Nanobody) are numbered according to thegeneral numbering for VHs given by Kabat et al. (“Sequence of proteinsof immunological interest”, US Public Health Services, NIH Bethesda,Md., Publication No. 91), as applied to VHH domains from Camelids in thearticle of Riechmann and Muyldermans, J. Immunol. Methods 2000 Jun. 23;240 (1-2): 185-195; or referred to herein. It should be noted that, asis well known in the art for VH domains and for VHH domains, the totalnumber of amino acid residues in each of the CDRs may vary and may notcorrespond to the total number of amino acid residues indicated by theKabat numbering (that is, one or more positions according to the Kabatnumbering may not be occupied in the actual sequence, or the actualsequence may contain more amino acid residues than the number allowedfor by the Kabat numbering). This means that, generally, the numberingaccording to Kabat may or may not correspond to the actual numbering ofthe amino acid residues in the actual sequence.

Alternative methods for numbering the amino acid residues of VH domains,which methods can also be applied in an analogous manner to VHH domainsfrom Camelids and to Nanobodies, are the method described by Chothia etal. (Nature 342, 877-883 (1989)), the so-called “AbM definition” and theso-called “contact definition”. However, in the present description,aspects and figures, the numbering according to Kabat as applied to VHHdomains by Riechmann and Muyldermans will be followed, unless indicatedotherwise.

The invention also relates to CTLA4 binders (e.g., ISVD such as aNanobody); to methods for expressing/producing the CTLA4 binders of theinvention; to compositions and products (such as pharmaceuticalcompositions and products) that comprise the CTLA4 binders of theinvention; to polynucleotides that encode the CTLA4 binders of theinvention; and to uses (and in particular therapeutic, prophylactic anddiagnostic uses) of the CTLA4 binders of the invention.

These and other aspects, embodiments, advantages, applications and usesof the invention will become clear from the further description herein.

Accordingly, in a further aspect, the invention relates to polypeptidesor other chemical entities that comprise or essentially consist of atleast one (such as one, two or three) CTLA4 binding moieties describedherein. These molecules themselves may be referred to as “CTLA4 binders”or “compounds of the invention” or “polypeptides of the invention”.

CTLA4 binders (e.g., ISVD such as a Nanobody) of the invention cancontain one or more other amino acid sequences, chemical entities ormoieties. These other amino acid sequences, chemical entities ormoieties can confer one or more desired properties to the resultingCTLA4 binders of the invention and/or can alter the properties of theresulting CTLA4 binders of the invention in a desired manner, forexample to provide the resulting CTLA4 binders of the invention with adesired biological and/or therapeutic activity (for example, to providethe resulting CTLA4 binders of the invention with affinity andpreferably potency against another therapeutically relevant target suchthat the resulting polypeptide becomes “bispecific” with respect toCTLA4 and that other therapeutically relevant target such as PD1, LAG3,BTLA and/or CD27), to provide a desired half-life and/or to otherwisemodify or improve pharmacokinetic and/or pharmacodynamic properties, totarget the CTLA4 binder to specific cells, tissues or organs (includingcancer cells and cancer tissues), to provide a cytotoxic effect and/orto serve as a detectable tag or label. Some non-limiting examples ofsuch other amino acid sequences, chemical entities or moieties are:

-   -   one or more suitable linkers (such a 9GS, 15GS or 35GS linker        (any combination of 9, 15 or 35 G and S amino acids such as, for        example, GGGGSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGS)) (SEQ ID NO: 65).        In an embodiment of the invention, the linker is (GGGGS)_(n)(SEQ        ID NO: 118), wherein n is 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10;        and/or    -   one or more binding moieties, binding domains or binding units        that are directed against a therapeutically relevant target        other than CTLA4 (i.e. so as to provide a CTLA4 binder of the        invention that is bispecific for both CTLA4 and the other        therapeutically relevant target such as a different epitope of        CTLA4, PD1, CD27, LAG3, BTLA, TIM3, ICOS, B7-H3, B7-H4, CD137,        GITR, PD-L1, PD-L2, ILT1, ILT2 CEACAM1, CEACAM5, TIM3, TIGIT,        VISTA, ILT3, ILT4, ILT5, ILT6, ILT7, ILT8, CD40, OX40, CD137,        KIR2DL1, KIR2DL2, KIR2DL3, KIR2DL4, KIR2DL5A, KIR2DL5B, KIR3DL1,        KIR3DL2, KIR3DL3, NKG2A, NKG2C, NKG2E, IL-10, IL-17, TSLP))        and/or    -   one or more binding domains or binding units that provide for an        increase in half-life (for example, a binding domain or binding        unit that can bind against a serum protein such as serum        albumin); and/or    -   one or more binding moieties, binding domains or binding units        that target the CTLA4 binder (e.g., ISVD such as a Nanobody) to        a desired cell, tissue or organ (such as a cancer cell); and/or    -   one or more binding moieties, binding domains or binding units        that provide for increased specificity against CTLA4 (usually,        these will be able to bind to CTLA4 but will generally by        themselves essentially not be functional against CTLA4); and/or    -   a binding moiety, binding domain, binding unit or other chemical        entity that allows for the CTLA4 binder to be internalized into        a (desired) cell (for example, an internalizing anti-EGFR        Nanobody as described in WO 2005/044858); and/or    -   a moiety that improves half-life such as a suitable        polyethyleneglycol group (i.e. PEGylation) or an amino acid        sequence that provides for increased half-life such as human        serum albumin or a suitable fragment thereof (i.e. albumin        fusion) or for example a serum albumin binding peptide as        described in WO 2008/068280; and/or    -   a payload such as a cytotoxic payload; and/or    -   a detectable label or tag, such as a radiolabel or fluorescent        label; and/or    -   a tag that can help with immobilization, detection and/or        purification of the CTLA4 binder, such as a HIS or FLAG3 tag;        and/or    -   a tag that can be functionalized, such as a C-terminal GGC or        GGGC tag; and/or    -   a C-terminal extension X(n), which may be as further described        herein for the CTLA4 binders of the invention and/or as        described in WO 2012/175741 or PCT/EP2015/060643        (WO2015/173325).

CTLA4 binders (e.g., ISVD such as a Nanobody) that also contain one ormore parts or fragments of a (preferably human) conventional antibody(such as an Fc part or a functional fragment thereof or one or moreconstant domains) and/or from a Camelid heavy-chain only antibody (suchas one or more constant domains) are part of the present invention.

Multispecific Binders

The present invention includes CTLA4 binders that may be fused in asingle multivalent (e.g., multispecific) molecule that also binds toCTLA4 or to another polypeptide and, in an embodiment of the invention,such binders are linked to one or more half-life extenders thatincreases the half-life of the binders in the body of a subject (e.g.,comprising the amino acid sequence set forth in SEQ ID NO: 62 or 64). Inan embodiment of the invention, the half-life extender is an ISVD (e.g.,a Nanobody) that specifically binds to human serum albumin (HSA), e.g.,ALB 11002. In an embodiment of the invention, the multispecific binderis F023700912 or F023700914 as described herein.

A polypeptide may be “fused to” another molecule either directly, withno linker, or through a linker such as a peptide linker, e.g., 35GS.

Multispecific binders may include a CTLA4 binder as well as a one ormore binders that bind to an additional antigen such as CD27, PD1, LAG3,BTLA, TIM3, ICOS, B7-H3, B7-H4, CD137, GITR, PD-L1, PD-L2, ILT1, ILT2CEACAM1, CEACAM5, TIM3, TIGIT, VISTA, ILT3, ILT4, ILT5, ILT6, ILT7,ILT8, CD40, OX40, CD137, KIR2DL1, KIR2DL2, KIR2DL3, KIR2DL4, KIR2DL5A,KIR2DL5B, KIR3DL1, KIR3DL2, KIR3DL3, NKG2A, NKG2C, NKG2E, IL-10, IL-17or TSLP.

For some specific but non-limiting examples of such ISVD-based orNanobody-based biologicals, reference is to the various applications byAblynx N. V., such as for example and without limitation WO 2004/062551,WO 2006/122825, WO 2008/020079 and WO 2009/068627, as well as forexample, and without limitation, to applications such as WO 2006/038027,WO 2006/059108, WO 2007/063308, WO 2007/063311, WO 2007/066016 and WO2007/085814. Also, as further described herein, a further moiety, whichmay be part of a molecule set forth in the applications mentioned above,may be an ISVD or Nanobody as described herein, directed against a(human) serum protein such as (human) serum albumin, and such an ISVD orNanobody (e.g., ALB 11002) may also find therapeutic uses, in particularin and/or for extending the half-life of the CTLA4 binders (andpolypeptides comprising the same) that are described herein. Referenceis for example made to WO 2004/041865, WO 2006/122787 and WO2012/175400, which generally describe the use of serum-albumin bindingNanobodies for half-life extension. WO 2009/138519 (or in the prior artcited in WO 2009/138519) or WO 2008/020079 (or in the prior art cited inWO 2008/020079) are incorporated by reference. Also, where a method ortechnique is not specifically described herein, it can, in an embodimentof the invention, be performed as described in WO 2009/138519 (or in theprior art cited in WO 2009/138519) or WO 2008/020079 (or in the priorart cited in WO 2008/020079).

When the CTLA4 binders (e.g., ISVD such as a Nanobody) contain one ormore further binding moieties, binding domains or binding units (e.g. afurther essentially non-functional binding domain or binding unitagainst CTLA4 that provides for increased specificity against CTLA4, abinding moiety, binding domain or binding unit against a therapeutictarget other than CTLA4, a binding moiety, binding domain or bindingunit against a target such as human serum albumin that provides forincreased half-life, and/or a binding moiety, binding domain or bindingunit that targets the CTLA4 binder to a specific cell, tissue or organand/or that allows for the CTLA4 binder to be internalized into a cell),these other binding moieties, binding domains or binding unitspreferably comprise one or more ISVDs, and more preferably are allISVDs. For example and without limitation, these one or more furtherbinding domains or binding units can be one or more Nanobodies(including a VHH, a humanized VHH and/or a camelized VHs such ascamelized human VHs), a (single domain) antibody that is a VH domain orthat is derived from a VH domain, a dAb that is or essentially consistsof a VH domain or that is derived from a VH domain, or even a (single)domain antibody or a dAb that is or essentially consists of VL domain.In particular, these one or more binding domains or binding units, whenpresent, may comprise one or more Nanobodies, and more in particular areall Nanobodies.

When a CTLA4 binder of the invention has an ISVD at its C-terminal end(which C-terminal ISVD may be a CTLA4 binding moiety described herein ormay for example be, if present in the CTLA4 binder, a furtheressentially non-functional ISVD against CTLA4 that provides forincreased specificity against CTLA4, an ISVD against a therapeutictarget other than CTLA4, an ISVD against a target such as human serumalbumin that provides for increased half-life, or an ISVD that targetsthe CTLA4 binder to a specific cell, tissue or organ and/or that allowsfor the CTLA4 binder to be internalized into a cell), then the CTLA4binding moiety (i.e. said C-terminal ISVD) preferably has a C-terminalextension X(n), which C-terminal extension may be as described hereinfor the CTLA4 binders of the invention and/or as described in WO2012/175741 or PCT/EP2015/060643 (WO2015/173325).

When a CTLA4 binder (e.g., ISVD such as a Nanobody) contains, inaddition to the one or more CTLA4 binding moieties described herein, anyfurther ISVDs (which one or more further ISVDs may, as mentioned, be afurther essentially non-functional ISVD against CTLA4 that provides forincreased specificity against CTLA4, an ISVD against a therapeutictarget other than CTLA4, an ISVD against a target such as human serumalbumin that provides for increased half-life, and/or an ISVD thattargets the CTLA4 binder to a specific cell, tissue or organ and/or thatallows for the CTLA4 binder to be internalized into a cell), and wheresuch further ISVDs are Nanobodies or are ISVDs that are, thatessentially consist of and/or that are derived from VH sequences, thenaccording to a preferred aspect of the invention said one or more (andpreferably all) further ISVDs present in the CTLA4 binder will containwithin their sequence one or more framework mutations that reducebinding by pre-existing antibodies. In particular, according to thisaspect of the invention, such further ISVDs may contain (a suitablecombination of) amino acid residues/mutations at positions 11, 89, 110and/or 112 that are as described in PCT/EP2015/060643 (WO2015/173325)and/or that essentially are as described herein for the CTLA4 binders ofthe invention. In one specific aspect, when the CTLA4 binder has such anISVD at its C-terminal end (i.e. does not have CTLA4 binding moiety ofthe invention at its C-terminal end), then at least said ISVD that ispresent at and/or forms the C-terminal end has such framework mutationsthat reduce binding by pre-existing antibodies (and said C-terminal ISVDwill preferably also have a C-terminal extension X(n) as describedherein).

As mentioned, when the CTLA4 binder (e.g., ISVD such as a Nanobody) isto have an increased half-life (i.e. compared to the monovalent CTLA4binder of the invention), the CTLA4 binder preferably contains at leastone (such as one) ISVD (and in particular Nanobody) that provides forsuch increased half-life. Such an ISVD will usually be directed againsta suitable serum protein such as transferrin and in particular against(human) serum albumin. In particular, such an ISVD or Nanobody may be a(single) domain antibody or dAb against human serum albumin as describedin for example EP 2 139 918, WO 2011/006915, WO 2012/175400, WO2014/111550 and may in particular be a serum albumin binding Nanobody asdescribed in WO 2004/041865, WO 2006/122787, WO 2012/175400 orPCT/EP2015/060643 (WO2015/173325). Particularly preferred serum albuminbinding ISVDs are the Nanobody Alb-1 (see WO 2006/122787) or itshumanized variants such as Alb-8 (WO 2006/122787, SEQ ID NO: 62), Alb-23(WO 2012/175400, SEQ ID NO: 1) and other humanized (and preferably alsosequence-optimized) variants of Alb-1 and/or variants of Alb-8 or Alb-23(or more generally ISVDs that have essentially the same CDRs as Alb-1,Alb-8 and Alb-23).

In an embodiment of the invention, the ISVD (e.g., Nanobody) is ALB11002 which binds to human serum albumin. ALB 11002 is summarized belowin Table C.

The present invention includes CTLA4 binders comprising an HSA binder ofthe invention, for example, having the same combination of CDRs (i.e.CDR1, CDR2 and CDR3) as are present in ALB 11002 or in a bindercomprising the sequence of SEQ ID NO: 66. See Table C.

TABLE C Human Serum Albumin (HSA) Binder ALB11002 SEQ ID NO DescriptionSequence 66 ALB11002 EVQLVESGGG XVQPGNSLRL SCAASGFTFS SFGMSWVRQA PGKGLEWVS S ISGSGSDTL Y ADSVKGRFTI SRDNAKTTLY LQMNSLRPED TAXYYCTIGG SLSR SSQGTL VTVSSA; wherein X at residues 11 and 93are L or V; for example, EVQLVESGGGVVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGS DTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTALYYCTIGGSLSRSSQGTLVTVSS (SEQ ID NO: 112) 67 CDR1GFTFSSFGMS or SFGMS (SEQ ID NO: 113; amino acids 6-10 of SEQ ID NO: 67)68 CDR2 SISGSGSDTLYADSVKG or SISGSGSDTL(SEQ ID NO: 114; amino acids 1-10   of SEQ ID NO: 68) 69 CDR3 GGSLSR

Optionally, ALB 11002 lacks the C-terminal Alanine. In an embodiment ofthe invention, the HSA binder comprises the amino acid sequence of SEQID NO: 66 but including a mutatoin at position 1, 1, 89, 110 or 112,e.g., comprising a set of mutations set forth in Table C herein.

Residue 1 of SEQ ID NO: 66 can be D or E. If residue 1 is D, the HSAbinder may be designated as 1D and if residue 1 is E, the HSA binder maybe designated as 1E.

The present invention includes HSA binders comprising one, two or threeof the CDRs of a HSA binder wherein each comprises 0, 1, 2, 3, 4, 5, 6,7, 8, 9 or 10 amino acid substitutions, e.g., conservativesubstitutions, and/or comprises 100, 99, 98, 97, 96 or 95% sequenceidentity relative to the CDRs that are in the HSA binder sequences setforth of Table C or are set forth in SEQ ID NOs: 67-69, wherein an HSAbinder having such CDRs retains the ability to bind to HSA.

In an embodiment of the invention, the half-life extender is an anti-HSAISVD (e.g., a Nanobody) comprising:

-   -   a CDR1 that comprises the amino acid sequence GFTFSSFGMS (SEQ ID        NO: 67); and    -   a CDR2 that comprises the amino acid sequence SISGSGSDTL (SEQ ID        NO: 114; and    -   a CDR3 that comprises the amino acid sequence GGSLSR (SEQ ID NO:        69);        and, optionally, having:    -   a degree of sequence identity with the amino acid sequence of        SEQ ID NO: 66 (in which any C-terminal extension that may be        present as well as the CDRs are not taken into account for        determining the degree of sequence identity) of at least 85%,        preferably at least 90%, more preferably at least 95% (in which        the CDRs, any C-terminal extension that may be present, as well        as the mutations at positions 1, 11, 89, 110 and/or 112 required        by the specific aspect involved are not taken into account for        determining the degree of sequence identity);        and/or    -   no more than 7, such as no more than 5, preferably no more than        3, such as only 3, 2 or 1 “amino acid differences” (as defined        herein, and not taking into account any of the above-listed        mutations at position(s) 1, 11, 89, 110 and/or 112 that may be        present and not taking into account any C-terminal extension        that may be present) with the amino acid sequence of SEQ ID NO:        66 (in which said amino acid differences, if present, may be        present in the frameworks and/or the CDRs but are preferably        present only in the frameworks and not in the CDRs);        and optionally having:    -   a C-terminal extension (X)_(n), in which n is 1 to 10,        preferably 1 to 5, such as 1, 2, 3, 4 or 5 (and preferably 1 or        2, such as 1); and each X is an (preferably naturally occurring)        amino acid residue that is independently chosen, and preferably        independently chosen from the group consisting of alanine (A),        glycine (G), valine (V), leucine (L) or isoleucine (I).

Again, as mentioned, such a serum albumin binding ISVD, when present,may contain within its sequence one or more framework mutations thatreduce binding by pre-existing antibodies. In particular, when such aserum albumin binding ISVD is a Nanobody or a (single) domain antibodythat is, essentially consist of and/or is derived from a VH domain, theserum albumin binding ISVD may contain (a suitable combination of) aminoacid residues/mutations at positions 11, 89, 110 and/or 112 that are asdescribed in PCT/EP2015/060643 (WO2015/173325) and/or that essentiallyare as described herein for the CTLA4 binders of the invention. Forexample, PCT/EP2015/060643 (WO2015/173325) describes a number ofvariants of Alb-1, Alb-8 and Alb-23 that contain amino acidresidues/mutations at positions 11, 89, 110 and/or 112 that reducebinding by pre-existing antibodies that can be used in the CTLA4 bindersof the invention.

Again, when such a serum albumin binding ISVD is present at theC-terminal end of a CTLA4 binder (e.g., ISVD such as a Nanobody) of theinvention, the serum albumin binding ISVD (and as a result, the CTLA4binder of the invention) preferably has a C-terminal extension X_((n)),which C-terminal extension may be as described herein for the CTLA4binders of the invention and/or as described in WO 2012/175741 orPCT/EP2015/060643 (WO2015/173325). It also preferably has mutations thatreduce the binding of pre-existing antibodies, like (a suitablecombination of) the amino acid residues/mutations at positions 11, 89,110 and/or 112 described in PCT/EP2015/060643 (WO2015/173325).

However, as mentioned, other means of increasing the half-life of aCTLA4 binder of the invention (such as PEGylation, fusion to humanalbumin or a suitable fragment thereof, or the use of a suitable serumalbumin-binding peptide), are also included in the scope of theinvention.

Generally, when a CTLA4 binder (e.g., ISVD such as a Nanobody) of theinvention has increased half-life (e.g. through the presence of ahalf-life increasing ISVD or any other suitable way of increasinghalf-life), the resulting CTLA4 binder preferably has a half-life (asdefined herein) that is at least 2 times, preferably at least 5 times,for example at least 10 times or more than 20 times, greater than thehalf-life of the monovalent CTLA4 binder of the invention (as measuredin either in man and/or a suitable animal model, such as mouse orcynomolgus monkey). In particular, a CTLA4 binder of the inventionpreferably has a half-life (as defined herein) in human subjects of atleast 1 day, preferably at least 3 days, more preferably at least 7days, such as at least 10 days.

It will be clear from the disclosure herein that CTLA4 binder of theinvention (e.g., that are based on one or more ISVDs such as Nanobodies)can have different “formats”, i.e. essentially be monovalent, bivalentor trivalent, can be monospecific, bispecific, trispecific etc., and canbe biparatopic (as defined herein and in for example WO 2009/068625).For example, a CTLA4 binder of the invention can be:

-   -   (essentially) monovalent, i.e. (essentially) comprising a single        CTLA4 binding moiety of the invention. As mentioned, when used        in monovalent format, a CTLA4 binder of the invention preferably        has a C-terminal extension X(n) as further described herein.        Such a CTLA4 binder of the invention may also be half-life        extended;    -   (essentially) bivalent or trivalent and monospecific. Such a        CTLA4 binder of the invention will comprise two or more binding        moieties (e.g., ISVDs) against CTLA4, which may be the same or        different and when different may be directed against the same        epitope on CTLA4 or against different epitopes on CTLA4 (in the        latter case, so as to provide a biparatopic or multiparatopic        CTLA4 binder of the invention). Such a CTLA4 binder of the        invention may also be half-life extended;    -   (essentially) bivalent, trivalent (or multivalent) and        bispecific or trispecific (or multispecific). Such a CTLA4        binder of the invention will be directed against CTLA4 and at        least one other target. As described herein, said other target        may for example be another therapeutically relevant target (i.e.        other than CTLA4), such as, for example, PD1, LAG3, BTLA and/or        CD27, so as to provide a CTLA4 binder that is bispecific with        regards to CTLA4 and said other therapeutic target. Said other        target may also be a target that provides for increased        half-life (such as human serum albumin), so as to provide a        CTLA4 binder of the invention that has increased half-life. As        also mentioned herein, such other target may allow also for the        CTLA4 binder of the invention to be targeted to specific cells,        tissues or organs or may allow for the CTLA4 binder of the        invention to be internalized into a cell. It is also possible to        combine these approaches/ISVDs, for example to provide a CTLA4        binder of the invention that is bispecific for CTLA4 and for at        least one other therapeutically relevant target and that is        half-life extended.

Again, preferably, when these CTLA4 binder (e.g., ISVD such as aNanobody) of the invention contain one or more binding moieties (e.g.,ISVDs) other than the at least one CTLA4 binder of the invention, atleast one and preferably all of these other ISVDs will contain withinits sequence one or more framework mutations that reduce binding bypre-existing antibodies (such as, in particular, a combination of aminoacid residues/mutations at positions 11, 89, 110 and/or 112 that is asdescribed herein for the CTLA4 binders of the invention and/or asgenerally described in PCT/EP2015/060643 (WO2015/173325)). Also, whensuch CTLA4 binder of the invention have a CTLA4 binding moiety at theirC-terminal end, then said C-terminal CTLA4 binding moiety (and as aresult, the CTLA4 binder of the invention) will preferably have aC-terminal extension X(n) as described herein. Similarly, when suchCTLA4 binder of the invention have another ISVD at their C-terminal end(i.e. not a CTLA4 binding moiety of the invention, but for example ahalf-life extending ISVD), then said C-terminal ISVD (and as a result,the CTLA4 binder of the invention) will preferably have a C-terminalextension X(n) as described herein and/or will contain within itssequence one or more framework mutations that reduce binding bypre-existing antibodies (again, as further described herein and inPCT/EP2015/060643 (WO2015/173325)).

As will be clear to the skilled person, when a CTLA4 binder (e.g., ISVDsuch as a Nanobody) of the invention is intended for topical use (i.e.on the skin or in the eye) or is for example meant to have a (localized)therapeutic action somewhere in for example the GI tract (i.e. afteroral administration or administration by suppository) or in the lungs(i.e. after administration by inhalation) or is otherwise meant to bedirectly applied to its intended place of action (for example, by directinjection), a CTLA4 binder of the invention may not require half-lifeextension. Also, for treatment of certain acute conditions orindications, it may be preferable not to have a prolonged half-life. Inthese cases, the use of a monovalent CTLA4 binder of the invention or ofa CTLA4 binder of the invention (comprising the CTLA4 binding moiety ofthe invention) without half-life extension (for example, a CTLA4 binderof the invention that is bivalent or biparatopic with respect to CTLA4)is preferred.

Some preferred, but non-limiting examples of such CTLA4 binder (e.g.,ISVD such as a Nanobody) of the invention are schematically representedin Table C-1 below, and each of these forms a further aspect of theinvention. Other examples of suitable CTLA4 binders of the inventionwithout half-life extension will be clear to the skilled person based onthe disclosure herein.

TABLE C-1 Schematic representation of some CTLA4 binders of theinvention without a half-life extending ISVD. [CTLA4 binding moiety][CTLA4 binding moiety]-X(n) [CTLA4 binding moiety]-[CTLA4 bindingmoiety] [CTLA4 binding moiety]-[CTLA4 binding moiety]-X(n) [CTLA4binding moiety]-[Other] [CTLA4 binding moiety]-[Other]-X(n)[Other]-[CTLA4 binding moiety] [Other]-[CTLA4 binding moiety]-X(n)[CTLA4 binding moiety]-[Targeting unit] [Targeting unit]-[CTLA4 bindingmoiety] [CTLA4 binding moiety]-[Targeting unit]-X(n) [Targetingunit]-[CTLA4 binding moiety]-X(n) [CTLA4 binding moiety]-[CTLA4 bindingmoiety]-[Targeting unit] [CTLA4 binding moiety]-[CTLA4 bindingmoiety]-[Targeting unit]-X(n) [Targeting unit]-[CTLA4 bindingmoiety]-[CTLA4 binding moiety] [Targeting unit]-[CTLA4 bindingmoiety]-[CTLA4 binding moiety]-X(n) Legend: “[CTLA4 binding moiety]”represents a CTLA4 binding domain or unit (e.g., an ISVD such as aNanobody), e.g., 11F01 (E1D, L11V, A14P, Q45R, A74S, K83R, V89L, M96P,Q108L). “-” represents either a direct covalent linkage or a suitablelinker, such as a 9GS, 15GS or 35GS linker “X(n)” represents aC-terminal extension as defined herein such as a single alanine residue.“[Other]” represents a binding domain or binding unit (e.g., an ISVDsuch as a Nanobody) against CTLA4 different from the CTLA4 bindingmoiety or against a different antigen such as PD1, LAG3, CD27 and/orBTLA. “[Targeting unit]” represents a binding domain or binding unit(e.g., an ISVD such as a Nanobody) that targets the CTLA4 binder of theinvention to a specific cell, tissue or organ

As will be clear to the skilled person, when a CTLA4 binder (e.g., ISVDsuch as a Nanobody) of the invention is intended for systemicadministration and/or for prevention and/or treatment of a chronicdisease or disorder, it will usually be preferred that said CTLA4 binderof the invention has increased half-life (as defined herein). Morepreferably, such a CTLA4 binder of the invention will contain ahalf-life extending ISVD such as, preferably, an ISVD and in particulara Nanobody binding to human serum albumin (as described herein).

Some preferred, but non-limiting examples of such CTLA4 binders (e.g.,ISVD such as a Nanobody) of the invention are schematically representedin Table C-2 below, and each of these forms a further aspect of theinvention. Other examples of suitable CTLA4 binder of the invention withhalf-life extension will be clear to the skilled person based on thedisclosure herein. Generally, for CTLA4 binder of the invention withhalf-life extension, the presence of a C-terminal extension is muchpreferred.

TABLE C-2 Schematic Representation of Some CTLA4 Binders of theInvention with a Half Life Extending ISVD. [CTLA4 binding moiety]-[HLE][HLE]-[CTLA4 binding moiety] [CTLA4 binding moiety]-[HLE]-X(n)[HLE]-[CTLA4 binding moiety]-X(n) [CTLA4 binding moiety]-[CTLA4 bindingmoiety]-[HLE] [CTLA4 binding moiety]-[HLE]-[CTLA4 binding moiety][HLE]-[CTLA4 binding moiety]-[CTLA4 binding moiety] [CTLA4 bindingmoiety]-[CTLA4 binding moiety]-[HLE]-X(n) [CTLA4 bindingmoiety]-[HLE]-[CTLA4 binding moiety]-X(n) [HLE]-[CTLA4 bindingmoiety]-[CTLA4 binding moiety]-X(n) [CTLA4 binding moiety]-[Other]-[HLE][CTLA4 binding moiety]-[HLE]-[Other] [HLE]-[CTLA4 bindingmoiety]-[Other] [HLE]-[Other]-[CTLA4 binding moiety] [Other]-[CTLA4binding moiety]-[HLE] [Other]-[HLE]-[CTLA4 binding moiety] [CTLA4binding moiety]-[Other]-[HLE]-X(n) [CTLA4 bindingmoiety]-[HLE]-[Other]-X(n) [HLE]-[CTLA4 binding moiety]-[Other]-X(n)[HLE]-[Other]-[CTLA4 binding moiety]-X(n) [Other]-[CTLA4 bindingmoiety]-[HLE]-X(n) [Other]-[HLE]-[CTLA4 binding moiety]-X(n) [CTLA4binding moiety]-[Targeting unit]-[HLE] [CTLA4 bindingmoiety]-[HLE]-[Targeting unit] [HLE]-[CTLA4 binding moiety]-[Targetingunit] [Targeting unit]-[CTLA4 binding moiety]-[HLE] [Targetingunit]-[HLE]-[CTLA4 binding moiety] [HLE]-[Targeting unit]-[CTLA4 bindingmoiety] [CTLA4 binding moiety]-[Targeting unit]-[HLE]-X(n) [CTLA4binding moiety]-[HLE]-[Targeting unit]-X(n) [HLE]-[CTLA4 bindingmoiety]-[Targeting unit]-X(n) [Targeting unit]-[CTLA4 bindingmoiety]-[HLE]-X(n) [Targeting unit]-[HLE]-[CTLA4 binding moiety]-X(n)[HLE]-[Targeting unit]-[CTLA4 binding moiety]-X(n) [CTLA4 bindingmoiety]-[CTLA4 binding moiety]-[Targeting unit]-[HLE] [CTLA4 bindingmoiety]-[CTLA4 binding moiety]-[HLE]-[Targeting unit] [CTLA4 bindingmoiety]-[HLE]-[CTLA4 binding moiety]-[Targeting unit] [HLE]-[CTLA4binding moiety]-[CTLA4 binding moiety]-[Targeting unit] [CTLA4 bindingmoiety]-[CTLA4 binding moiety]- [Targeting unit]-[HLE]-X(n) [CTLA4binding moiety]-[CTLA4 binding moiety]-[HLE]- [Targeting unit]-X(n)[CTLA4 binding moiety]-[HLE]-[CTLA4 binding moiety]- [Targetingunit]-X(n) [HLE]-[CTLA4 binding moiety]-[CTLA4 binding moiety]-[Targeting unit]-X(n) [Targeting unit]-[CTLA4 binding moiety]-[CTLA4binding moiety]-[HLE] [Targeting unit]-[CTLA4 bindingmoiety]-[HLE]-[CTLA4 binding moiety] [Targeting unit]-[HLE]-[CTLA4binding moiety]-[CTLA4 binding moiety] [HLE]-[Targeting unit]-[CTLA4binding moiety]-[CTLA4 binding moiety] [Targeting unit]-[CTLA4 bindingmoiety]-[CTLA4 binding moiety]- [HLE]-X(n) [Targeting unit]-[CTLA4binding moiety]-[HLE]- [CTLA4 binding moiety]-X(n) [Targetingunit]-[HLE]-[CTLA4 binding moiety]- [CTLA4 binding moiety]-X(n)[HLE]-[Targeting unit]-[CTLA4 binding moiety]- [CTLA4 bindingmoiety]-X(n) Legend: “[CTLA4 binding moiety]” represents a CTLA4 bindingunit or domain (e.g., an ISVD such as a Nanobody), e.g., 11F01 (E1D,L11V, A14P, Q45R, A74S, K83R, V89L, M96P, Q108L). “-” represents eithera direct covalent linkage or a suitable linker, such as a 9GS, 15GS or35GS linker “X(n)” represents a C-terminal extension as defined hereinsuch as a single alanine residue. “[HLE]” represents a half-lifeextending binding domain or binding unit (and in particular a half-lifeextending ISVD), such as an ISVD (and in particular Nanobody) against(human) serum albumin, e.g., ALB11002; “[Other]” represents a bindingdomain or binding unit (and in particular ISVD such as a Nanobody)against CTLA4 different from the “CTLA4 binding moiety” or againstanother antigen such as PD1, LAG3, CD27 and/or BTLA. “[Targeting unit]”represents a binding domain or binding unit (and in particular ISVD suchas a Nanobody) that targets the CTLA4 binder to a specific cell, tissueor organ

The present invention also provides a CTLA4 ISVD, F023700912, comprisingamino acid sequence:

DVQLVESGGGVVQPGGSLRLSCAASGGTFS FYGMG WFRQAPGKEREEVADIRTSAGRTYYADSVKGRFTISRDNSKNTVYLQMNSLRPEDTALYY

VQLVESGGGVVQPGGSLRLSCAASGGTFS FYGMG WFRQAPGKEREEVA DIRTSAGRTYYA

TFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTALYYCTIGGSLSRSSQGTLVTVSSA(SEQ ID NO: 62; 35GS linkers underscored with dotted line; CDRsunderscored and/or bold). Optionally, the first residue of any bindermoiety in the molecule is substituted with a D or an E as appropriate.

Optionally, the CTLA4 ISVD comprises a signal peptide such as:

(SEQ ID NO: 70)MRFPSIFTAVLFAASSALAAPVNTTTEDETAQIPAEAVIGYSDLEGDFDVAVLPFSNSTNNGLLFINTTIASIAAKEEGVSLEKRF023700912 can be encoded by a polynucleotide comprising the followingnucleotides:gacgtgcaat tggtggagtc tgggggagga gtggtgcagc cggggggctc tctgagactc 60tcctgtgcag cctctggtgg caccttcagt ttctatggca tgggctggtt ccgccaggct 120ccagggaagg agcgcgagtt tgtagcagat attagaacca gtgctggtag gacatactat 180gcagactccg tgaagggccg attcaccatc tccagagaca acagcaagaa cacggtgtat 240ctgcaaatga acagcctgcg ccctgaggac acggccctgt attactgtgc agcagagcca 300agtggaataa gtggttggga ctactggggc caggggaccc tggtcacggt ctcctccgga 360ggcggtgggt caggtggcgg aggcagcggt ggaggaggta gtggcggtgg cggtagtggg 420ggtggaggca gcggaggcgg aggcagtggg ggcggtggat ccgaggtgca gttggtggag 480tctgggggag gagtggtgca gccggggggc tctctgagac tctcctgtgc agcctctggt 540ggcaccttca gtttctatgg catgggctgg ttccgccagg ctccagggaa ggagcgcgag 600tttgtagcag atattagaac cagtgctggt aggacatact atgcagactc cgtgaagggc 660cgattcacca tctccagaga caacagcaag aacacggtgt atctgcaaat gaacagcctg 720cgccctgagg acacggccct gtattactgt gcagcagagc caagtggaat aagtggttgg 780gactactggg gccaggggac cctggtcacg gtctcgagcg gaggcggtgg gtcaggtggc 840ggaggcagcg gtggaggagg tagtggcggt ggcggtagtg ggggtggagg cagcggaggc 900ggaggcagtg ggggcggtgg ctcagaggta caactagtgg agtctggagg tggcgttgtg 960caaccgggta acagtctgcg ccttagctgc gcagcgtctg gctttacctt cagctccttt 1020ggcatgagct gggttcgcca ggctccggga aaaggactgg aatgggtttc gtctattagc 1080ggcagtggta gcgatacgct ctacgcggac tccgtgaagg gccgtttcac catctcccgc 1140gataacgcca aaactacact gtatctgcaa atgaatagcc tgcgtcctga agatacggcc 1200ctgtattact gtactattgg tggctcgtta agccgttctt cacagggtac cctggtcacc 1260gtctcctcag cg 1272(SEQ ID NO: 61; optionally lacking the signal sequence of nucleotides1-255)

F023700912 comprises the following moieties:

-   -   CTLA4 binder 11F01(E1D,L11V,A14P,Q45R,A74S,K83R,V89L,M96P,Q108L)    -   35 GS linker    -   CTLA4 binder 11F01(L11V,A14P,Q45R,A74S,K83R,V89L,M96P,Q108L)    -   35 GS linker    -   Human serum albumin binder ALB 11002;    -   C-terminal extension alanine.

For example:

-   -   CTLA4 binder SEQ ID NO: 60    -   35GS linker SEQ ID NO: 65    -   CTLA4 binder SEQ ID NO: 60 (DIE)    -   35GS linker SEQ ID NO: 65    -   Human serum albumin binder SEQ ID NO: 66    -   Alanine

(the present invention includes any binder including such an arrangementof moieties)

The present invention also provides a CTLA4 ISVD, F023700914, comprisingamino acid sequence:

DVQLVESGGGVVQPGGSLRLSCAASGGTFS FYGMG WERQAPGKEREEVADIRTSAGRTYYADSVKGRFTISRDNSKNTVYLQMNSLRPEDTALYY

VQLVESGGGVVQPGNSLRLSCAASGETFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTALYYCTIGGSLSRSSQGTLVTVSSA(SEQ ID NO: 64; 35GS linker underscored with dotted line; CDRsunderscored and/or bold). Optionally, the first residue of any bindermoiety in the molecule is substituted with a D or an E as appropriate.

Optionally, the CTLA4 ISVD comprises a signal peptide such as:

(SEQ ID NO: 70) MRFPSIFTAVLFAASSALAAPVNTTTEDETAQIPAEAVIGYSDLEGDFDVAVLPFSNSTNNGLLFINTTIASIAAKEEGVSLEKR

F023700914 can be encoded by a polynucleotide comprising the followingnucleotides:

gacgtgcaat tggtggagtc tgggggagga gtggtgcagc cggggggctc tctgagactc 60tcctgtgcag cctctggtgg caccttcagt ttctatggca tgggctggtt ccgccaggct 120ccagggaagg agcgcgagtt tgtagcagat attagaacca gtgctggtag gacatactat 180gcagactccg tgaagggccg attcaccatc tccagagaca acagcaagaa cacggtgtat 240ctgcaaatga acagcctgcg ccctgaggac acggccctgt attactgtgc agcagagcca 300agtggaataa gtggttggga ctactggggc caggggaccc tggtcacggt ctcctccgga 360ggcggtgggt caggtggcgg aggcagcggt ggaggaggta gtggcggtgg cggtagtggg 420ggtggaggca gcggaggcgg aggcagtggg ggcggtggat ccgaggtgca gttggtggag 480tctggaggtg gcgttgtgca accgggtaac agtctgcgcc ttagctgcgc agcgtctggc 540tttaccttca gctcctttgg catgagctgg gttcgccagg ctccgggaaa aggactggaa 600tgggtttcgt ctattagcgg cagtggtagc gatacgctct acgcggactc cgtgaagggc 660cgtttcacca tctcccgcga taacgccaaa actacactgt atctgcaaat gaatagcctg 720cgtcctgaag atacggccct gtattactgt actattggtg gctcgttaag ccgttcttca 780cagggtaccc tggtcaccgt ctcctcagcg 810(SEQ ID NO: 63; optionally lacking the signal sequence of nucleotides1-255)

F023700914 comprises the following moieties:

-   -   CTLA4 binder 11F01        (E1D,L11V,A14P,Q45R,A74S,K83R,V89L,M96P,Q108L);    -   35 GS linker;    -   Human serum albumin binder ALB 11002;    -   C-terminal extension alanine.        For example:    -   CTLA4 binder SEQ ID NO: 60    -   35GS linker SEQ ID NO: 65    -   Human serum albumin binder SEQ ID NO: 66    -   Alanine        (the present invention includes any binder including such an        arrangement of moieties)

The present invention includes any multispecific CTLA4 binder comprisingthe amino acid sequence of SEQ ID NO: 62 or 64 or an amino acid sequencecomprising 80% or more (e.g., 85%, 90%, 95%, 96%, 97%, 98% or 99%) aminoacid sequence identity wherein the CTLA4 binder retains the ability tobind to CTLA4 and, optionally, HSA.

Epitope Binding and Cross-Blocking

The present invention provides CTLA4 binders set forth herein (e.g.,F023700912 or F023700914) as well as binders, e.g., comprising CTLA4ISVDs (e.g., Nanobodies) that bind to the same CTLA4 epitope of suchbinders. For example, the present invention includes binders that bindto human CTLA4 by contacting the same residues as F023700912 orF023700914. For example, the present invention provides binders thatbind to human CTLA4 at residues VRVTVL (SEQ ID NO: 118; amino acids33-38 of SEQ ID NO: 110), ADSQVTEVC (SEQ ID NO: 119; amino acids 41-49of SEQ ID NO: 110) and CKVELMYPPPYYLG (SEQ ID NO: 120; amino acids93-106 of SEQ ID NO: 110), e.g., all three sites, of human CTLA4. In anembodiment of the invention, the binder demonstrates binding to humanCTLA4 at these residues in a hydrogen-deuterium exchange assay, e.g.,protects the residues from exchange of hydrogen for deuterium in thepresence of deuterium such as D₂O, e.g., as represented by a bindingheat map essentially as set forth in FIG. 13 .

The present invention includes a CTLA4 binder (e.g., F023700912 orF023700914 or 11F01 or any of its variants set forth herein) that isbound to a polypeptide that comprises the peptide sequences VRVTVL (SEQID NO: 118; amino acids 33-38 of SEQ ID NO: 110), ADSQVTEVC (SEQ ID NO:119; amino acids 41-49 of SEQ ID NO: 110) and CKVELMYPPPYYLG (SEQ ID NO:120; amino acids 93-106 of SEQ ID NO: 110), for example, CTLA4.Optionally, the polypeptide is on the surface of a cell, e.g., a T-celland the polypeptide is bound by the CTLA4 binder.

The present invention also provides cross-blocking binders that are ableto cross-block binding of any of the binders disclosed herein (e.g.,F023700912 or F023700914). Such cross-blocking binders may be anymolecule that exhibits such cross-blocking, e.g., an ISVD, Nanobody,antibody or antigen-binding fragment thereof.

In general, a binder (e.g., ISVD such as Nanobody) or antibody orantigen-binding fragment thereof that “cross-blocks” a reference binderrefers to a binder (e.g., ISVD such as Nanobody) or antibody orantigen-binding fragment thereof that blocks binding of the referencebinder to its antigen in a competition assay by 50% or more, andconversely, the reference binder blocks binding of the binder (e.g.,ISVD such as Nanobody) or antibody or antigen-binding fragment thereofto its antigen in a competition assay by 50% or more. Cross-blocking canbe determined any assay known in the art, including surface plasmonresonance (SPR), ELISA and flow cytometry.

In an embodiment of the invention, cross-blocking is determined by useof a Biacore assay. For convenience, reference is made to two binders,however, the scope of the present invention includes antibodies andantigen binding fragments thereof, e.g., Fab fragments, that cross-blocka binder of the present invention. A Biacore machine (for example theBiacore 3000) is operated in line with the manufacturer'srecommendations.

Thus, in one cross-blocking assay, CTLA4 is coupled to a CM5 Biacorechip using standard amine coupling chemistry to generate a CTLA4-coatedsurface. For example, 200-800 resonance units of CTLA4 would be coupledto the chip (or any amount that gives easily measurable levels ofbinding but that is readily saturable by the concentrations of testreagent being used).

The two binders (termed A* and B*) to be assessed for their ability tocross-block each other are mixed at a one to one molar ratio of bindingsites in a suitable buffer to create the test mixture.

The concentration of each binder in the test mix should be high enoughto readily saturate the binding sites for that binder on the CTLA4molecules captured on the Biacore chip. The binders in the mixture areat the same molar concentration.

Separate solutions containing binder A* alone and binder B* alone arealso prepared. Binder A* and binder B* in these solutions should be inthe same buffer and at the same concentration as in the test mix.

The test mixture is passed over the CTLA4-coated Biacore chip and thetotal amount of binding recorded. The chip is then treated in such a wayas to remove the bound binders without damaging the chip-bound CTLA4. Inan embodiment of the invention, this is done by treating the chip with30 mM HCl for 60 seconds.

The solution of binder A* alone is then passed over the CTLA4-coatedsurface and the amount of binding recorded. The chip is again treated toremove all of the bound binder without damaging the chip-bound CTLA4.

The solution of binder B* alone is then passed over the CTLA4-coatedsurface and the amount of binding recorded.

The maximum theoretical binding of the mixture of binder A* and binderB* is next calculated, and is the sum of the binding of each binder whenpassed over the CTLA4 surface alone. If the actual recorded binding ofthe mixture is less than this theoretical maximum, then the two bindersare cross-blocking each other.

Thus, in general, a cross-blocking binder according to the invention isone which will bind to CTLA4 in the above Biacore cross-blocking assaysuch that, during the assay and in the presence of a second binder, therecorded binding is between, for example, 80% and 0.1% (e.g., 80% to 4%)of the maximum theoretical binding, for example between 75% and 0.1%(e.g., 75% to 4%) of the maximum theoretical binding, for example,between 70% and 0.1% (e.g., 70% to 4%) of maximum theoretical binding(as just defined above) of the two binders in combination.

In an embodiment of the invention, an ELISA assay is used fordetermining whether a CTLA4 binder cross-blocks or is capable ofcross-blocking according to the invention.

The general principal of the assay is to have an CTLA4 binder coatedonto the wells of an ELISA plate. An excess amount of a second,potentially cross-blocking, CTLA4 binder is added in solution (i.e., notbound to the ELISA plate). A limited amount of CTLA4 is then added tothe wells. The coated binder and the binder in solution compete forbinding of the limited number of CTLA4 molecules. The plate is washed toremove CTLA4 that has not been bound by the coated binder and to alsoremove the second, solution phase binder as well as any complexes formedbetween the second, solution phase binder and CTLA4. The amount of boundCTLA4 is then measured using an appropriate CTLA4 detection reagent. Abinder in solution that is able to cross-block the coated binder will beable to cause a decrease in the number of CTLA4 molecules that thecoated binder can bind relative to the number of CTLA4 molecules thatthe coated binder can bind in the absence of the second, solution phase,binder.

Expression Methods

The present invention includes recombinant methods for making an CTLA4binders (e.g., an ISVD such as a Nanobody) of the present invention(e.g., F023700912 or F023700914) comprising (i) introducing apolynucleotide encoding the amino acid sequence of said CTLA4 binder,for example, wherein the polynucleotide is in a vector and/or isoperably linked to a promoter; (ii) culturing the host cell (e.g., CHOor Pichia or Pichia pastoris) under condition favorable to expression ofthe polynucleotide and, (iii) optionally, isolating the CTLA4 binderfrom the host cell and/or medium in which the host cell is grown. Seee.g., WO 04/041862, WO 2006/122786, WO 2008/020079, WO 2008/142164 or WO2009/068627.

The invention also relates to polynucleotides that encode CTLA4 bindersof the present invention (e.g., an ISVD such as a Nanobody) as describedherein (e.g., F023700912 or F023700914). The polynucleotides may, in anembodiment of the invention, be operably linked to one or more controlsequences. The polynucleotide may be in the form of a plasmid or vector.Again, such polynucleotides can be generally as described in thepublished patent applications of Ablynx N. V., such as for example WO04/041862, WO 2006/122786, WO 2008/020079, WO 2008/142164 or WO2009/068627.

The invention also relates to hosts or host cells that contain suchpolynucleotides, vectors, and/or CTLA4 binders described herein (e.g.,F023700912 or F023700914). Again, such host cells can be generally asdescribed in the published patent applications of Ablynx N. V., such asfor example WO 04/041862, WO 2006/122786, WO 2008/020079, WO 2008/142164or WO 2009/068627. Examples of specific host cells are discussed below.

Eukaryotic and prokaryotic host cells, including mammalian cells ashosts for expression of the CTLA4 binder (e.g., ISVD such as a Nanobody)are well known in the art and include many immortalized cell linesavailable from the American Type Culture Collection (ATCC). Theseinclude, inter alia, Chinese hamster ovary (CHO) cells, NSO, SP2 cells,HeLa cells, baby hamster kidney (BHK) cells, monkey kidney cells (COS),human hepatocellular carcinoma cells (e.g., Hep G2), A549 cells, 3T3cells, HEK-293 cells and a number of other cell lines. Mammalian hostcells include human, mouse, rat, dog, monkey, pig, goat, bovine, horseand hamster cells. Cell lines of particular preference are selectedthrough determining which cell lines have high expression levels. Othercell lines that may be used are insect cell lines (e.g., Spodopterafrugiperda or Trichoplusia ni), amphibian cells, bacterial cells, plantcells and fungal cells. Fungal cells include yeast and filamentousfungus cells including, for example, Pichia pastoris, Pichia finlandica,Pichia trehalophila, Pichia koclamae, Pichia membranaefaciens, Pichiaminuta (Ogataea minuta, Pichia lindneri), Pichia opuntiae, Pichiathermotolerans, Pichia salictaria, Pichia guercuum, Pichia pijperi,Pichia stiptis, Pichia methanolica, Pichia sp., Saccharomycescerevisiae, Saccharomyces sp., Hansenula polymorpha, Kluyveromyces sp.,Kluyveromyces lactis, Candida albicans, Aspergillus nidulans,Aspergillus niger, Aspergillus oryzae, Trichoderma reesei, Chrysosporiumlucknowense, Fusarium sp., Fusarium gramineum, Fusarium venenatum,Physcomitrella patens and Neurospora crassa. Pichia sp., anySaccharomyces sp., Hansenula polymorpha, any Kluyveromyces sp., Candidaalbicans, any Aspergillus sp., Trichoderma reesei, Chrysosporiumlucknowense, any Fusarium sp., Yarrowia lipolytica, and Neurosporacrassa. The present invention includes any host cell (e.g., a CHO cellor Pichia cell, e.g., Pichia pastoris) containing an CTLA4 binder of thepresent invention (e.g., F023700912 or F023700914) or containing apolynucleotide encoding such a binder or containing a vector thatcontains the polynucleotide.

Further, expression of a CTLA4 binder (e.g., an ISVD such as a Nanobody)from production cell lines can be enhanced using a number of knowntechniques. For example, the glutamine synthetase gene expression system(the GS system) is a common approach for enhancing expression undercertain conditions. The GS system is discussed in whole or part inconnection with European Patent Nos. 0 216 846, 0 256 055, and 0 323 997and European Patent Application No. 89303964.4. Thus, in an embodimentof the invention, the mammalian host cells (e.g., CHO) lack a glutaminesynthetase gene and are grown in the absence of glutamine in the mediumwherein, however, the polynucleotide encoding the immunoglobulin chaincomprises a glutamine synthetase gene which complements the lack of thegene in the host cell. Such host cells containing the binder orpolynucleotide or vector as discussed herein as well as expressionmethods, as discussed herein, for making the binder using such a hostcell are part of the present invention.

The present invention includes methods for purifying a CTLA4 binder(e.g., ISVD such as a Nanobody) comprising introducing a sample (e.g.,culture medium, cell lysate or cell lysate fraction, e.g., a solublefraction of the lysate) comprising the CTLA4 binder to a purificationmedium (e.g., cation-exchange medium, anion-exchange medium, hydrophobicexchange medium, affinity purification medium (e.g., protein-A,protein-G, protein-A/G, protein-L)) and either collecting purified CTLA4binder from the flow-through fraction of said sample that does not bindto the medium; or, discarding the flow-through fraction and elutingbound CTLA4 binder from the medium and collecting the eluate. In anembodiment of the invention, the medium is in a column to which thesample is applied. In an embodiment of the invention, the purificationmethod is conducted following recombinant expression of the antibody orfragment in a host cell, e.g., wherein the host cell is first lysed and,optionally, the lysate is purified of insoluble materials prior topurification on a medium; or wherein the CTLA4 binder is secreted intothe culture medium by the host cell and the medium or a fraction thereofis applied to the purification medium.

In general, glycoproteins produced in a particular cell line ortransgenic animal will have a glycosylation pattern that ischaracteristic for glycoproteins produced in the cell line or transgenicanimal. Therefore, the particular glycosylation pattern of a CTLA4binder (e.g., ISVD such as a Nanobody) will depend on the particularcell line or transgenic animal used to produce the CTLA4 binder. CTLA4binders comprising only non-fucosylated N-glycans are part of thepresent invention and may be advantageous, because non-fucosylatedantibodies have been shown to typically exhibit more potent efficacythan their fucosylated counterparts both in vitro and in vivo (See forexample, Shinkawa et al., J. Biol. Chem. 278: 3466-3473 (2003); U.S.Pat. Nos. 6,946,292 and 7,214,775). These CTLA4 binders withnon-fucosylated N-glycans are not likely to be immunogenic because theircarbohydrate structures are a normal component of the population thatexists in human serum IgG.

The present invention includes CTLA4 binders comprising N-linked glycansthat are typically added to immunoglobulins produced in Chinese hamsterovary cells (CHO N-linked glycans) or to engineered yeast cells(engineered yeast N-linked glycans), such as, for example, Pichiapastoris. For example, in an embodiment of the invention, the CTLA4binder (e.g., ISVD such as a Nanobody) comprises one or more of the“engineered yeast N-linked glycans” or “CHO N-linked glycans” that areset forth in FIG. 4 (e.g., G0 and/or G0-F and/or G1 and/or G1-F and/orG2-F and/or Man5). In an embodiment of the invention, the CTLA4 bindercomprises the engineered yeast N-linked glycans, i.e., G0 and/or G1and/or G2, optionally, further including Man5. In an embodiment of theinvention, the CTLA4 binders comprise the CHO N-linked glycans, i.e.,G0-F, G1-F and G2-F, optionally, further including G0 and/or G1 and/orG2 and/or Man5. In an embodiment of the invention, about 80% to about95% (e.g., about 80-90%, about 85%, about 90% or about 95%) of allN-linked glycans on the CTLA4 binders are engineered yeast N-linkedglycans or CHO N-linked glycans. See Nett et al. Yeast. 28(3): 237-252(2011); Hamilton et al. Science. 313(5792): 1441-1443 (2006); Hamiltonet al. Curr Opin Biotechnol. 18(5): 387-392 (2007). For example, in anembodiment of the invention, an engineered yeast cell is GFI5.0 orYGLY8316 or strains set forth in U.S. Pat. No. 7,795,002 or Zha et al.Methods Mol Biol. 988:31-43 (2013). See also international patentapplication publication no. WO2013/066765.

Combinations

In particular embodiments, the CTLA4 binders (e.g., ISVD such as aNanobody) of the present invention may be used alone, or in associationwith other, further therapeutic agents and/or therapeutic procedures,for treating or preventing any disease such as cancer, e.g., asdiscussed herein, in a subject in need of such treatment or prevention.Compositions or kits, e.g., pharmaceutical compositions comprising apharmaceutically acceptable carrier, comprising such CTLA4 binders inassociation with further therapeutic agents are also part of the presentinvention.

The term “in association with” indicates that the components, a CTLA4binder (e.g., ISVD such as a Nanobody) of the present invention alongwith another agent such as pembrolizumab or nivolumab, can be formulatedinto a single composition, e.g., for simultaneous delivery, orformulated separately into two or more compositions (e.g., a kit). Eachcomponent can be administered to a subject at a different time than whenthe other component is administered; for example, each administrationmay be given non-simultaneously (e.g., separately or sequentially) atintervals over a given period of time. Moreover, the separate componentsmay be administered to a subject by the same or by a different route(e.g., wherein a CTLA4 binder of the present invention is administeredparenterally and paclitaxel is administered orally).

In particular embodiments, the CTLA4 binders (e.g., ISVD such as aNanobody) may be used in association with an anti-cancer therapeuticagent or immunomodulatory drug such as an immunomodulatory receptorinhibitor, e.g., an antibody or antigen-binding fragment thereof thatspecifically binds to the receptor.

In an embodiment of the invention, a CTLA4 binder (e.g., ISVD such as aNanobody) is in association with one or more of an inhibitors (e.g., asmall organic molecule or an antibody or antigen-binding fragmentthereof) such as: an MTOR (mammalian target of rapamycin) inhibitor, acytotoxic agent, a platinum agent a BRAF inhibitor, a CDK4/6 inhibitoran EGFR inhibitor, a VEGF inhibitor, a microtubule stabilizer, a taxane,a CD20 inhibitor, a CD52 inhibitor, a CD30 inhibitor, a RANK (Receptoractivator of nuclear factor kappa-B) inhibitor, a RANKL (Receptoractivator of nuclear factor kappa-B ligand) inhibitor, an ERK inhibitor,a MAP Kinase inhibitor, an AKT inhibitor, a MEK inhibitor, a PI3Kinhibitor, a HER1 inhibitor, a HER2 inhibitor, a HER3 inhibitor, a HER4inhibitor, a Bcl2 inhibitor, a CD22 inhibitor, a CD79b inhibitor, anErbB2 inhibitor, or a farnesyl protein transferase inhibitor.

In an embodiment of the invention, a CTLA4 binder (e.g., ISVD such as aNanobody) is in association with one or more of: anti-CTLA4 antibodiesor antigen-binding fragments thereof (e.g., ipilimumab), anti-PD1antibody or antigen-binding fragment thereof (e.g., pembrolizumab,nivolumab, CT-011), anti-PDL1, anti-CTLA4, anti-TIM3, anti-CS1, (e.g.,elotuzumab), anti-KIR2DL1/2/3 (e.g., lirilumab), anti-CD27, anti-CD137(e.g., urelumab), anti-GITR (e.g., TRX518), anti-PD-L1 (e.g.,BMS-936559, MSB0010718C or MPDL3280A), anti-PD-L2, anti-ILT1, anti-ILT2,anti-ILT3, anti-ILT4, anti-ILT5, anti-ILT6, anti-ILT7, anti-ILT8,anti-CD40, anti-OX40, anti-CD137, anti-KIR2DL1, anti-KIR2DL2/3,anti-KIR2DL4, anti-KIR2DL5A, anti-KIR2DL5B, anti-KIR3DL1, anti-KIR3DL2,anti-KIR3DL3, anti-NKG2A, anti-NKG2C, anti-NKG2E, or any small organicmolecule inhibitor of such targets; IL-10, anti-IL 10, anti-TSLP (thymicstromal lymphopoietin) or PEGylated IL-10.

In an embodiment of the invention, the molecular weight of thepolyethylene glycol (PEG) moiety, on a PEGylated IL-10 molecule, isabout 12,000 daltons or about 20,000 daltons.

In an embodiment of the invention, PEGylated IL-10 (e.g., PEGylatedhuman IL-10) comprises one or more polyethylene glycol moleculescovalently attached via a linker (e.g., C₂₋₁₂ alkyl such as —CH₂CH₂CH₂—)to a single amino acid residue of a single subunit of IL-10, whereinsaid amino acid residue is the alpha amino group of the N-terminal aminoacid residue or the epsilon amino group of a lysine residue. In anembodiment of the invention PEGylated IL-10 is: (PEG)_(b)-L-NH-IL-10;wherein b is 1-9 and L is a C₂₋₁₂ alkyl linker moiety covalentlyattached to a nitrogen (N) of the single amino acid residue of theIL-10. In an embodiment of the invention, the IL-10 of PEGylated IL-10has the formula: [X—O(CH₂CH₂O)_(n)]_(b)-L-NH-IL-10, wherein X is H orC₁₋₄ alkyl; n is 20 to 2300; b is 1 to 9; and L is a C₁₋₁₁ alkyl linkermoiety which is covalently attached to the nitrogen (N) of the alphaamino group at the amino terminus of one IL-10 subunit; provided thatwhen b is greater than 1, the total of n does not exceed 2300. See U.S.Pat. No. 7,052,686.

In an embodiment of the invention, the anti-IL-10 antibody orantigen-binding fragment thereof (e.g., humanized antibody) comprisesthe CDRs set forth below:

CDR-L1: (SEQ ID NO: 71) KTSQNIFENLA; CDR-L2: (SEQ ID NO: 72) NASPLQA;CDR-L3: (SEQ ID NO: 73) HQYYSGYT; CDR-H1: (SEQ ID NO: 74) GFTFSDYHMA;CDR-H2: (SEQ ID NO: 75) SITLDATYTYYRDSVRG; CDR-H3: (SEQ ID NO: 76)HRGFSVWLDY; (See U.S. Pat. No. 7,662,379)

In an embodiment of the invention, the anti-TSLP antibody orantigen-binding fragment thereof (e.g., humanized antibody) comprisesthe CDRs set forth below:

CDR-H1: (SEQ ID NO: 77) GYIFTDYAMH; CDR-H2: (SEQ ID NO: 78)TFIPLLDTSDYNQNFK; CDR-H3: (SEQ ID NO: 79) MGVTHSYVMDA; CDR-Ll:(SEQ ID NO: 80) RASQPISISVH; CDR-L2: (SEQ ID NO: 81) FASQSIS; CDR-L3:(SEQ ID NO: 82) QQTFSLPYT; (see WO2008/76321)

In an embodiment of the invention, the anti-CD27 antibody orantigen-binding fragment thereof (e.g., humanized antibody) comprisesthe CDRs set forth below:

CDR-H1: (SEQ ID NO: 83) GFIIKATYMH; CDR-H2: (SEQ ID NO: 84)RIDPANGETKYDPKFQV; CDR-H3: (SEQ ID NO: 85) YAWYFDV; CDR-L1:(SEQ ID NO: 86) RASENIYSFLA; CDR-L2: (SEQ ID NO: 87) HAKTLAE; CDR-L3:(SEQ ID NO: 88) QHYYGSPLT; (See WO2012/04367).

Thus, the present invention includes compositions comprising a CTLA4binder (e.g., ISVD such as a Nanobody) in association withpembrolizumab; as well as methods for treating or preventing cancer in asubject comprising administering an effective amount of the CTLA4 binderin association with pembrolizumab (e.g., pembrolizumab dosed at 200 mgonce every three weeks) to the subject. Optionally, the subject is alsoadministered in association with a another further therapeutic agent.

In an embodiment of the invention, a CTLA4 binder (e.g., ISVD such as aNanobody) is in association with a pembrolizumab antibody whichcomprises an immunoglobulin heavy chain (or CDR-H1, CDR-H2 and CDR-H3thereof) comprising the amino acid sequence:QVQLVQSGVEVKKPGASVKVSCKASGYTFTNYYMYWVRQAPGQGLEWMGGINPSNGGTNFNEKFKNRVTLTTDSSTTTAYMELKSLQFDDTAVYYCARRDYRFDMGFDYWGQGTTVTVSSASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTKTYTCNVDHKPSNTKVDKRVESKYGPPCPPCPAPEFLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSQEDPEVQFNWYVDGVEVHNAKTKPREEQFNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKGLPSSIEKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTVDKSRWQEGNVFSCSVMHEALHNHYTQKSLSLSLGK; (SEQ ID NO:89) and an immunoglobulin light chain (or CDR-L1, CDR-L2 and CDR-L3thereof) comprising the amino acid sequence:

(SEQ ID NO: 90) EIVLTQSPATLSLSPGERATLSCRASKGVSTSGYSYLHWYQQKPGQAPRLLIYLASYLESGVPARFSGSGSGTDFTLTISSLEPEDFAVYYCQHSRDLPLTFGGGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC.

In an embodiment of the invention, a CTLA4 binder (e.g., ISVD such as aNanobody) is in association with an antibody comprising animmunoglobulin heavy chain (or CDR-H1, CDR-H2 and CDR-H3 thereof)comprising the amino acid sequence:QVQLVESGGGVVQPGRSLRLDCKASGITFSNSGMHWVRQAPGKGLEWVAVIWYDGSKRYYADSVKGRFTISRDNSKNTLFLQMNSLRAEDTAVYYCATNDDYWGQGTLVTVSSASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTKTYTCNVDHKPSNTKVDKRVESKYGPPCPPCPAPEFLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSQEDPEVQFNWYVDGVEVHNAKTKPREEQFNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKGLPSSIEKTISKAKGQPREPQVYTLPPSQEEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTVDKSRWQEGNVFSCSVMHEALHNHYTQKSLSLSLGK (SEQ ID NO: 91); andan immunoglobulin light chain (or CDR-L1, CDR-L2 and CDR-L3 thereof)comprising the amino acid sequence:

(SEQ ID NO: 92) EIVLTQSPATLSLSPGERATLSCRASQSVSSYLAWYQQKPGQAPRLLIYDASNRATGIPARFSGSGSGTDFTLTISSLEPEDFAVYYCQQSSNWPRTFGQGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEV THQGLSSPVTKSFNRGEC.

In an embodiment of the invention, a CTLA4 binder is in association withany one or more of: 13-cis-retinoic acid, 3-[5-(methylsulfonylpiperadinemethyl)-indolyl]-quinolone, 4-hydroxytamoxifen,5-deooxyuridine, 5′-deoxy-5-fluorouridine, 5-fluorouracil,6-mecaptopurine, 7-hydroxystaurosporine, A-443654, abirateroneacetate,abraxane, ABT-578, acolbifene, ADS-100380, aflibercept, ALT-110,altretamine, amifostine, aminoglutethimide, amrubicin, amsacrine,anagrelide, anastrozole, angiostatin, AP-23573, ARQ-197, arzoxifene,AS-252424, AS-605240, asparaginase, ATI3387, AT-9263, atrasentan,axitinib, AZD1152, Bacillus Calmette-Guerin (BCG) vaccine, batabulin,BC-210, besodutox, bevacizumab, BGJ398, bicalutamide, Bio111, BIO1140,BKM120, bleomycin, BMS-214662, BMS-247550, BMS-275291, BMS-310705,bortezimib, buserelin, busulfan, calcitriol, camptothecin, canertinib,capecitabine, carboplatin, carmustine, CC8490, CEA (recombinantvaccinia-carcinoembryonic antigen vaccine), cediranib, CG-1521, CG-781,chlamydocin, chlorambucil, chlorotoxin, cilengitide, cimitidine,cisplatin, cladribine, clodronate, cobimetnib, COL-3, CP-724714,cyclophosphamide, cyproterone, cyproteroneacetate, cytarabine,cytosinearabinoside, dabrafenib, dacarbazine, dacinostat, dactinomycin,dalotuzumab, danusertib, dasatanib, daunorubicin, decatanib, deguelin,denileukin, deoxycoformycin, depsipeptide, diarylpropionitrile,diethylstilbestrol, diftitox, DNE03, docetaxel, dovitinib, doxorubicin,droloxifene, edotecarin, yttrium-90 labeled-edotreotide, edotreotide,EKB-569, EMD121974, encorafenib, endostatin, enzalutamide, enzastaurin,epirubicin, epithilone B, ERA-923, erbitux, erlotinib, estradiol,estramustine, etoposide, everolimus, exemestane, ficlatuzumab,finasteride, flavopiridol, floxuridine, fludarabine, fludrocortisone,fluoxymesterone, flutamide, FOLFOX regimen, fulvestrant, galeterone,ganetespib, gefitinib, gemcitabine, gimatecan, glucopyranosyl lipid A,goserelin, goserelin acetate, gossypol, GSK461364, GSK690693, HMR-3339,hydroxyprogesteronecaproate, hydroxyurea, IC87114, idarubicin,idoxyfene, ifosfamide, IM862, imatinib, IMC-1C11, imiquimod, INC280,INCB24360, INO1001, interferon, interleukin-2, interleukin-12,ipilimumab, irinotecan, JNJ-16241199, ketoconazole, KRX-0402, lapatinib,lasofoxifene, LEE011, letrozole, leucovorin, leuprolide, leuprolideacetate, levamisole, liposome entrapped paclitaxel, lomustine,lonafarnib, lucanthone, LY292223, LY292696, LY293646, LY293684,LY294002, LY317615, LY3009120, marimastat, mechlorethamine,medroxyprogesteroneacetate, megestrolacetate, MEK162, melphalan,mercaptopurine, mesna, methotrexate, mithramycin, mitomycin, mitotane,mitoxantrone, a suspension of heat killed Mycobacterium obuense,tozasertib, MLN8054, natitoclax, neovastat, Neratinib, neuradiab,nilotinib, nilutimide, nolatrexed, NVP-BEZ235, oblimersen, octreotide,ofatumumab, oregovomab, ornatuzumab, orteronel, oxaliplatin, paclitaxel,palbociclib, pamidronate, panitumumab, pazopanib, PD0325901, PD184352,PEG-interferon, pemetrexed, pentostatin, perifosine,phenylalaninemustard, PI-103, pictilisib, PIK-75, pipendoxifene,PKI-166, plicamycin, poly-ICLC, porfimer, prednisone, procarbazine,progestins, PSK protein bound polysaccharide (derived from Basidiomycetecoriolus versicolor), PLX8394, PX-866, R-763, raloxifene, raltitrexed,razoxin, ridaforolimus, rituximab, romidepsin, RTA744, rubitecan,scriptaid, Sdx102, seliciclib, selumetinib, semaxanib, SF1126,sirolimus, SN36093, sorafenib, spironolactone, squalamine, SR13668,streptozocin, SU6668, suberoylanalide hydroxamic acid, sunitinib,synthetic estrogen, talampanel, talimogene laherparepvec, tamoxifen,temozolomide, temsirolimus, teniposide, tesmilifene, testosterone,tetrandrine, TGX-221, thalidomide, 6-thioguanine, thiotepa, ticilimumab,tipifarnib, tivozanib, TKI-258, TLK286, TNF D (tumor necrosis factoralpha), topotecan, toremifene citrate, trabectedin, trametinib,trastuzumab, tretinoin, trichostatin A, triciribinephosphatemonohydrate, triptorelin pamoate, TSE-424, uracil mustard, valproicacid, valrubicin, vandetanib, vatalanib, VEGF trap, vemurafenib,vinblastine, vincristine, vindesine, vinorelbine, vitaxin, vitespan,vorinostat, VX-745, wortmannin, Xr311, Z-100 hot water extract ofBacillus tuberculosis, zanolimumab, ZK186619, ZK-304709, ZM336372 orZSTK474.

In an embodiment of the invention, a CTLA4 binder (e.g., ISVD such as aNanobody) is in association with one or more antiemetics including, butnot limited to: casopitant (GlaxoSmithKline), Netupitant (MGI-Helsinn)and other NK-1 receptor antagonists, palonosetron (sold as Aloxi by MGIPharma), aprepitant (sold as Emend by Merck and Co.; Rahway, N.J.),diphenhydramine (sold as Benadryl® by Pfizer; New York, N.Y.),hydroxyzine (sold as Atarax® by Pfizer; New York, N.Y.), metoclopramide(sold as Reglan® by AH Robins Co.; Richmond, Va.), lorazepam (sold asAtivan® by Wyeth; Madison, N.J.), alprazolam (sold as Xanax® by Pfizer;New York, N.Y.), haloperidol (sold as Haldol® by Ortho-McNeil; Raritan,N.J.), droperidol (Inapsine®), dronabinol (sold as Marinol® by SolvayPharmaceuticals, Inc.; Marietta, Ga.), dexamethasone (sold as Decadron®by Merck and Co.; Rahway, N.J.), methylprednisolone (sold as Medrol® byPfizer; New York, N.Y.), prochlorperazine (sold as Compazine® byGlaxosmithkline; Research Triangle Park, N.C.), granisetron (sold asKytril® by Hoffmann-La Roche Inc.; Nutley, N.J.), ondansetron (sold asZofran® by Glaxosmithkline; Research Triangle Park, N.C.), dolasetron(sold as Anzemet® by Sanofi-Aventis; New York, N.Y.), tropisetron (soldas Navoban® by Novartis; East Hanover, N.J.).

Other side effects of cancer treatment include red and white blood celldeficiency. Accordingly, in an embodiment of the invention, a CTLA4binder (e.g., ISVD such as a Nanobody) is in association with an agentwhich treats or prevents such a deficiency, such as, e.g., filgrastim,PEG-filgrastim, erythropoietin, epoetin alfa or darbepoetin alfa.

In an embodiment of the invention, a CTLA4 binder (e.g., ISVD such as aNanobody) is in association with a vaccine. In an embodiment of theinvention, the vaccine is an anti-cancer vaccine, a peptide vaccine or aDNA vaccine. For example, in an embodiment of the invention, the vaccineis a tumor cell (e.g., an irradiated tumor cell) or a dendritic cell(e.g., a dendritic cell pulsed with a tumor peptide).

In an embodiment of the invention, a CTLA4 binder (e.g., ISVD such as aNanobody) is administered in association with a therapeutic procedure. Atherapeutic procedure is one or more steps carried out by a physician orclinician in treating a subject which is intended to alleviate one ormore symptoms (e.g., of cancer and/or infectious disease) in the treatedsubject, whether by inducing the regression or elimination of suchsymptoms or by inhibiting the progression of such symptom(s), e.g.,cancer symptoms such as tumor growth or metastasis, by any clinicallymeasurable degree.

In an embodiment of the invention, a therapeutic procedure isanti-cancer radiation therapy. For example, in an embodiment of theinvention, the radiation therapy is external beam therapy (EBT): amethod for delivering a beam of high-energy X-rays to the location ofthe tumor. The beam is generated outside the patient (e.g., by a linearaccelerator) and is targeted at the tumor site. These X-rays can destroythe cancer cells and careful treatment planning allows the surroundingnormal tissues to be spared. No radioactive sources are placed insidethe patient's body. In an embodiment of the invention, the radiationtherapy is proton beam therapy: a type of conformal therapy thatbombards the diseased tissue with protons instead of X-rays. In anembodiment of the invention, the radiation therapy is conformal externalbeam radiation therapy: a procedure that uses advanced technology totailor the radiation therapy to an individual's body structures.

In an embodiment of the invention, the radiation therapy isbrachytherapy: the temporary placement of radioactive materials withinthe body, usually employed to give an extra dose—or boost—of radiationto an area.

In an embodiment of the invention, a surgical procedure administered inassociation with a CTLA4 binder (e.g., ISVD such as a Nanobody) issurgical tumorectomy.

Therapeutic Uses

The invention includes a method for the preventing and/or treating atleast one disease or disorder that can be prevented or treated by theuse of a CTLA4 binder (e.g., ISVD such as a Nanobody) of the presentinvention, optionally in association with a further therapeutic agent ortherapeutic procedure, which method comprises administering, to asubject in need thereof, a pharmaceutically active amount of the CTLA4binder, and/or of a pharmaceutical composition comprising the same.

“Treat” or “treating” means to administer a CTLA4 binder (e.g., ISVDsuch as a Nanobody) of the present invention, to a subject (e.g., amammal such as a human) having one or more symptoms of a disease forwhich the CTLA4 binders are effective, e.g., in the treatment of asubject having cancer or an infectious disease, or being suspected ofhaving cancer or infectious disease, for which the agent has therapeuticactivity. Typically, the CTLA4 binder is administered in an “effectiveamount” or “effective dose” which will alleviate one or more symptoms(e.g., of cancer or infectious disease) in the treated subject orpopulation, whether by inducing the regression or elimination of suchsymptoms or by inhibiting the progression of such symptom(s), e.g.,cancer symptoms such as tumor growth or metastasis, by any clinicallymeasurable degree. The effective amount of the CTLA4 binder may varyaccording to factors such as the disease stage, age, and weight of thepatient, and the ability of the drug to elicit a desired response in thesubject.

The subject to be treated may be any warm-blooded animal, but is inparticular a mammal, and more in particular a human being. As will beclear to the skilled person, the subject to be treated will inparticular be a person suffering from, or at risk from, the diseases anddisorders mentioned herein. Generally, the treatment regimen will befollowed until the desired therapeutic effect is achieved and/or for aslong as the desired therapeutic effect is to be maintained. Again, thiscan be determined by the clinician.

The CTLA4 binders (e.g., ISVD such as a Nanobody), polypeptides,compounds, and polynucleotides (e.g., vectors) described herein arepreferably administered to the circulation. As such, they can beadministered in any suitable manner that allows the CTLA4 binders,polypeptides, compounds, and polynucleotides to enter the circulation,such as intravenously, via injection or infusion, or in any othersuitable manner (including oral administration, subcutaneousadministration, intramuscular administration, administration through theskin, intranasal administration, administration via the lungs, etc.)that allows the CTLA4 binders, polypeptides, compounds, andpolynucleotides to enter the circulation. Suitable methods and routes ofadministration will be clear to the skilled person, again for examplealso from the teaching of the published patent applications of Ablynx N.V., such as for example WO 04/041862, WO 2006/122786, WO 2008/020079, WO2008/142164 or WO 2009/068627.

To prepare pharmaceutical or sterile compositions of the CTLA4 binders(e.g., ISVD such as a Nanobody) of the present invention, the CTLA4binders is admixed with a pharmaceutically acceptable carrier orexcipient. See, e.g., Remington's Pharmaceutical Sciences and U.S.Pharmacopeia: National Formulary, Mack Publishing Company, Easton, Pa.(1984) or Remington's Pharmaceutical Sciences. Such compositions arepart of the present invention.

The scope of the present invention includes dessicated, e.g.,freeze-dried, compositions comprising an CTLA4 binders (e.g., ISVD suchas a Nanobody) or a pharmaceutical composition thereof that includes apharmaceutically acceptable carrier but substantially lacks water.

Formulations of therapeutic and diagnostic agents may be prepared bymixing with acceptable carriers, excipients, or stabilizers in the formof, e.g., lyophilized powders, slurries, aqueous solutions orsuspensions (see, e.g., Hardman, et al. (2001) Goodman and Gilman's ThePharmacological Basis of Therapeutics, McGraw-Hill, New York, N.Y.;Gennaro (2000) Remington: The Science and Practice of Pharmacy,Lippincott, Williams, and Wilkins, New York, N.Y.; Avis, et al. (eds.)(1993) Pharmaceutical Dosage Forms: Parenteral Medications, MarcelDekker, NY; Lieberman, et al. (eds.) (1990) Pharmaceutical Dosage Forms:Tablets, Marcel Dekker, NY; Lieberman, et al. (eds.) (1990)Pharmaceutical Dosage Forms: Disperse Systems, Marcel Dekker, NY; Weinerand Kotkoskie (2000) Excipient Toxicity and Safety, Marcel Dekker, Inc.,New York, N.Y.).

Generally, for the prevention and/or treatment of the diseases anddisorders mentioned herein and depending on the specific disease ordisorder to be treated, the potency and/or the half-life of the specificfusion proteins or constructs to be used, the specific route ofadministration and the specific pharmaceutical formulation orcomposition used, the Nanobodies and polypeptides of the invention willgenerally be administered in an amount between 1 gram and 0.01 microgramper kg body weight per day, preferably between 0.1 gram and 0.1microgram per kg body weight per day, such as about 1, 10, 100 or 1000microgram per kg body weight per day, either continuously (e.g., byinfusion), as a single daily dose or as multiple divided doses duringthe day. The clinician will generally be able to determine a suitabledaily dose, depending on the factors mentioned herein. It will also beclear that in specific cases, the clinician may choose to deviate fromthese amounts, for example on the basis of the factors cited above andhis expert judgment. Generally, some guidance on the amounts to beadministered can be obtained from the amounts usually administered forcomparable conventional antibodies or antibody fragments against thesame target administered via essentially the same route, taking intoaccount however differences in affinity/avidity, efficacy,biodistribution, half-life and similar factors well known to the skilledperson.

The mode of administration of a CTLA4 binder (e.g., ISVD such as aNanobody) to a subject can vary. Routes of administration include oral,rectal, transmucosal, intestinal, parenteral; intramuscular,subcutaneous, intradermal, intramedullary, intrathecal, directintraventricular, intravenous, intraperitoneal, intranasal, intraocular,inhalation, insufflation, topical, cutaneous, transdermal, orintra-arterial.

Determination of the appropriate dose is made by the clinician, e.g.,using parameters or factors known or suspected in the art to affecttreatment. Generally, in determining the dose, the dose begins with anamount somewhat less than the optimum dose and it is increased by smallincrements thereafter until the desired or optimum effect is achievedrelative to any negative side effects. Important diagnostic measuresinclude those of symptoms of, e.g., the inflammation or level ofinflammatory cytokines produced. In general, it is desirable that abiologic that will be used is derived from the same species as theanimal targeted for treatment, thereby minimizing any immune response tothe reagent. In the case of human subjects, for example, chimeric,humanized and fully human antibodies are may be desirable. Guidance inselecting appropriate doses is available (see, e.g., Wawrzynczak (1996)Antibody Therapy, Bios Scientific Pub. Ltd, Oxfordshire, UK; Kresina(ed.) (1991) Monoclonal Antibodies, Cytokines and Arthritis, MarcelDekker, New York, N.Y.; Bach (ed.) (1993) Monoclonal Antibodies andPeptide Therapy in Autoimmune Diseases, Marcel Dekker, New York, N.Y.;Baert et al. (2003) New Engl. J. Med. 348:601-608; Milgrom et al. (1999)New Engl. J. Med. 341:1966-1973; Slamon et al. (2001) New Engl. J. Med.344:783-792; Beniaminovitz et al. (2000) New Engl. J. Med. 342:613-619;Ghosh et al. (2003) New Engl. J. Med. 348:24-32; Lipsky et al. (2000)New Engl. J. Med. 343:1594-1602).

Whether a disease symptom has been alleviated can be assessed by anyclinical measurement typically used by physicians or other skilledhealthcare providers to assess the severity or progression status ofthat symptom. While an embodiment of the present invention (e.g., atreatment method or article of manufacture) may not be effective inalleviating the target disease symptom(s) in every subject, it shouldalleviate the target disease symptom(s) in a statistically significantnumber of subjects as determined by any statistical test known in theart such as the Student's t-test, the chi²-test, the U-test according toMann and Whitney, the Kruskal-Wallis test (H-test),Jonckheere-Terpstra-test and the Wilcoxon-test.

Generally, the treatment regimen will be followed until the desiredtherapeutic effect is achieved and/or for as long as the desiredtherapeutic effect is to be maintained. Again, this can be determined bythe clinician.

As the CTLA4 binders (e.g., ISVD such as a Nanobody) of the presentinvention are capable of binding to CTLA4, they can in particular beused for treatment or prevention of cancer, metastatic cancer, a solidtumor, a hematologic cancer, leukemia, lymphoma, osteosarcoma,rhabdomyosarcoma, neuroblastoma, kidney cancer, leukemia, renaltransitional cell cancer, bladder cancer, Wilm's cancer, ovarian cancer,pancreatic cancer, breast cancer, prostate cancer, bone cancer, lungcancer, non-small cell lung cancer, gastric cancer, colorectal cancer,cervical cancer, synovial sarcoma, head and neck cancer, squamous cellcarcinoma, multiple myeloma, renal cell cancer, retinoblastoma,hepatoblastoma, hepatocellular carcinoma, melanoma, rhabdoid tumor ofthe kidney, Ewing's sarcoma, chondrosarcoma, brain cancer, glioblastoma,meningioma, pituitary adenoma, vestibular schwannoma, a primitiveneuroectodermal tumor, medulloblastoma, astrocytoma, anaplasticastrocytoma, oligodendroglioma, ependymoma, choroid plexus papilloma,polycythemia vera, thrombocythemia, idiopathic myelfibrosis, soft tissuesarcoma, thyroid cancer, endometrial cancer, carcinoid cancer or livercancer, breast cancer and gastric cancer.

CTLA4 binders (e.g., ISVD such as a Nanobody) of the present inventioncan be used for treatment or prevention of infectious diseases such as,for example, viral infection, bacterial infection, fungal infection orparasitic infection. In an embodiment of the invention, the viralinfection is infection with a virus selected from the group consistingof human immunodeficiency virus (HIV), ebola virus, hepatitis virus (A,B, or C), herpes virus (e.g., VZV, HSV-I, HAV-6, HSV-II, and CMV,Epstein Barr virus), adenovirus, influenza virus, flaviviruses,echovirus, rhinovirus, coxsackie virus, coronavirus, respiratorysyncytial virus, mumps virus, rotavirus, measles virus, rubella virus,parvovirus, vaccinia virus, HTLV virus, dengue virus, papillomavirus,molluscum virus, poliovirus, rabies virus, JC virus or arboviralencephalitis virus. In an embodiment of the invention, the bacterialinfection is infection with a bacteria selected from the groupconsisting of Chlamydia, rickettsial bacteria, mycobacteria,staphylococci, streptococci, pneumonococci, meningococci and gonococci,klebsiella, proteus, serratia, pseudomonas, Legionella, Corynebacteriumdiphtheriae, Salmonella, bacilli, Vibrio cholerae, Clostridium tetan,Clostridium botulinum, Bacillus anthricis, Yersinia pestis,Mycobacterium leprae, Mycobacterium lepromatosis, and Borriella. In anembodiment of the invention, the fungal infection is infection with afungus selected from the group consisting of Candida (albicans, krusei,glabrata, tropicalis, etc.), Cryptococcus neoformans, Aspergillus(fumigatus, niger, etc.), Genus Mucorales (mucor, absidia, rhizopus),Sporothrix schenkii, Blastomyces dermatitidis, Paracoccidioidesbrasiliensis, Coccidioides immitis and Histoplasma capsulatum. In anembodiment of the invention, the parasitic infection is infection with aparasite selected from the group consisting of Entamoeba histolytica,Balantidium coli, Naegleria fowleri, Acanthamoeba, Giardia lamnbia,Cryptosporidium, Pneumocystis carinii, Plasmodium vivax, Babesiamicroti, Trypanosoma brucei, Trypanosoma cruzi, Leishmania donovani,Toxoplasma gondii, Nippostrongylus brasiliensis.

The present invention also includes methods for:

-   -   preventing CTLA4 mediated inhibition of: T-cell costimulatory        signaling; T-cell activation, T-cell proliferation;    -   preventing CTLA4 binding to B7-1 (CD80) or B7-2 (CD86); and/or    -   enhancing T-cell activation        in the body of a subject by administering the CTLA4 binder        (e.g., F023700912 or F023700914) to the subject; or in vitro by        contacting CTLA4 with the CTLA4 binder. Such activities can be        mediated via the CTLA4 binder. Thus, such methods may also be        performed with any binder that includes a CTLA4 binder.

The invention also relates to methods of treatment of the aforementioneddiseases and disorders, which generally comprise administering to asubject in need thereof (i.e. suffering from one of the aforementioneddiseases) a therapeutically effective amount of a CTLA4 binder (e.g.,ISVD such as a Nanobody) of the invention. The invention also relates toa CTLA4 binder of the invention for use in the prevention or treatmentof one of the aforementioned diseases or disorders.

The present invention also provides an injection device comprising anyof the CTLA4 binders (e.g., ISVD such as a Nanobody), polypeptides orpolynucleotides set forth herein or a pharmaceutical compositionthereof. An injection device is a device that introduces a substanceinto the body of a patient via a parenteral route, e.g., intramuscular,subcutaneous or intravenous. For example, an injection device may be asyringe (e.g., pre-filled with the pharmaceutical composition, such asan auto-injector) which, for example, includes a cylinder or barrel forholding fluid to be injected (e.g., comprising the CTLA4 binder or apharmaceutical composition thereof), a needle for piecing skin and/orblood vessels for injection of the fluid; and a plunger for pushing thefluid out of the cylinder and through the needle bore. In an embodimentof the invention, an injection device that comprises an CTLA4 binder ora pharmaceutical composition thereof is an intravenous (IV) injectiondevice. Such a device includes the CTLA4 binder or a pharmaceuticalcomposition thereof in a cannula or trocar/needle which may be attachedto a tube which may be attached to a bag or reservoir for holding fluid(e.g., saline; or lactated ringer solution comprising NaCl, sodiumlactate, KCl, CaCl₂) and optionally including glucose) introduced intothe body of the subject through the cannula or trocar/needle. The CTLA4binder or a pharmaceutical composition thereof may, in an embodiment ofthe invention, be introduced into the device once the trocar and cannulaare inserted into the vein of a subject and the trocar is removed fromthe inserted cannula. The IV device may, for example, be inserted into aperipheral vein (e.g., in the hand or arm); the superior vena cava orinferior vena cava, or within the right atrium of the heart (e.g., acentral IV); or into a subclavian, internal jugular, or a femoral veinand, for example, advanced toward the heart until it reaches thesuperior vena cava or right atrium (e.g., a central venous line). In anembodiment of the invention, an injection device is an autoinjector; ajet injector or an external infusion pump. A jet injector uses ahigh-pressure narrow jet of liquid which penetrate the epidermis tointroduce the CTLA4 binder or a pharmaceutical composition thereof to apatient's body. External infusion pumps are medical devices that deliverthe CTLA4 binder or a pharmaceutical composition thereof into apatient's body in controlled amounts. External infusion pumps may bepowered electrically or mechanically. Different pumps operate indifferent ways, for example, a syringe pump holds fluid in the reservoirof a syringe, and a moveable piston controls fluid delivery, anelastomeric pump holds fluid in a stretchable balloon reservoir, andpressure from the elastic walls of the balloon drives fluid delivery. Ina peristaltic pump, a set of rollers pinches down on a length offlexible tubing, pushing fluid forward. In a multi-channel pump, fluidscan be delivered from multiple reservoirs at multiple rates.

It should also be noted that the Figures, any Sequence Listing and theExperimental Part/Examples are only given to further illustrate theinvention and should not be interpreted or construed as limiting thescope of the invention and/or of the appended claims in any way, unlessexplicitly indicated otherwise herein.

Other aspects, embodiments, advantages and applications of the inventionwill become clear from the further description herein.

EXAMPLES

These examples are intended to exemplify the present invention are not alimitation thereof. Compositions and methods set forth in the Examplesform part of the present invention.

Example 1: F023700906 Nanobody Binding to CTLA-4-Fc

Monovalent F023700906 Nanobody 11F01 (L11V,A14P,Q45R,A74S,K83R,V89L,M96P,Q108L)-FLAG3-HIS6), a building block of F023700912,demonstrates binding to CTLA-4-Fc fusion molecule from both human andcynomolgus monkey. On-rate, off-rate and affinity were determined on aProteOn XPR36 (BioRad 670BR0166) using human CTLA-4-hFc and cynomolgusmonkey CTLA4-hFc (Table D below). These results demonstratehigh-affinity binding of the Nanobody to human and cynomolgus monkeyCTLA-4 suggesting potential for the Nanobody to modulate the function ofCTLA-4 and that cynomolgus monkey may be used as a toxicology species.

TABLE D-1 Nanobody Binding to Human or Cynomolgous Monkey CTLA-4-FcHuman CTLA-4-Fc Cynomolgus CTLA-4-Fc Ka Kd KD Ka Kd KD (1/Ms) (1/s) (M)(1/Ms) (1/s) (M) F023700906 4.8E+06 5.9E−03 1.2E−09 4.7E+06 5.7E−031.2E−09

TABLE D-2 Reagents Expression Conc. Formulation SEC RP Reagent system(mg/ml) Buffer purity purity hCTLA4-Fc HEK293F 16.13 10 mM Sodium 94.86%61.50% Phosphate, (~150 KDa 75 mM (tetramer) NaCl, 3% Sucrose, pH = 7.4cynoCTLA4 HEK293EB 0.32 PBS pH 7.4 81.58% 83.50% -Fc NA

Example 2: F023700912 Nanobody Binding to Cell Surface CTLA4

F023700912 demonstrates binding to human CTLA-4 expressed on cellsurface. Binding of batches of F023700912 (11F01(E1D,L11V,A14P,Q45R,A74S,K83R,V89L,M96P,Q108L)-35GS-11F01(L11V,A14P,Q45R,A74S,K83R,V89L,M96P,Q108L)-35GS-ALB 11002-A]) (filledcircles), F023700925 (PD1 binder-35GS-PD1binder-35GS-11F01(L11V,A14P,Q45R,A74S,K83R,V89L,M96P,Q108L)-35GS-11F01(L11V,A14P,Q45R,A74S,K83R,V89L,M96P,Q108L)-35GS-ALB11002-A]) (filled squares) and an irrelavant Nb (filled triangles) to(A) bulksorted hCTLA4-overexpressing jurkat JE6.2.11 cells or (B)hCTLA4-overexpressing CHO-K1 cells was studied by flow cytometry.Nanobodies were detected via the ALB 11002-binding mAB ABH0074. The datagenerated in these experiments are set forth in FIG. 5 (A-B). Theseresults demonstrate binding of the F023700912 and F023700925 to CTLA-4expressed on cell surface suggesting that these Nanobodies modulate thefunction of CTLA-4.

FIG. 5 (A-B) is a dilution series (start concentration 1 μM, 1/4 serialdilution, 12 pts) of batches of half-life extended (ALB0011 buildingblock) Nbs F023700912 (filled circles), F023700925 (filled squares) andnegative control Nb IRR00051 (filled triangles) in 200 μl FACS buffer(PBS (Life Technologies, 14190-094), 10% heat-inactivated foetal bovineserum (Sigma, F7524), 0.05% NaN₃ (ThermoScientific, 19038)) were addedto (A) 2E4 bulksorted human CTLA4-overexpressing jurkat JE6.2.11cells/well or (B) 2E4 human CTLA4-overexpressing CHO-K1 cells/well andincubated for 30 minutes at 4° C.

After three washing steps (1 washing step=removal of Nb dilutions,addition of 100 μl cold FACS buffer, centrifugation for 5 minutes at 250g), the cells were incubated for 30 minutes at 4° C. with 3 μg/mlanti-ALB 11002 mouse mAb ABH00074 in cold FACS buffer for detection ofthe half-life-extended Nanobodies.

After three washing steps, the cells were incubated for 30 minutes at 4°C. with a 1/100 dilution in cold FACS buffer of PE goat F(ab′)2anti-mouse IgG (Jackson ImmunoResearch, 115-116-071).

After three washing steps, the cells were resuspended in 50 μl cold FACSbuffer supplemented with 5 nM TO-PRO-3 (Molecular Probes, T3605) andanalyzed with a FACS Canto.

First, a P1 population is selected based on FSC-SSC distribution.Stopping gate was set on 10000 cells in P1. From this population theTO-PRO-3+ cells (dead cells) are excluded. For this P1/TO-PRO-3-negativepopulation the median PE value is calculated.

Example 3: F023700912 Nanobody Blocks Binding of CTLA-4 to CD80 and CD86

F023700912 block binding of human CTLA-4 to its ligands CD80 and CD86.Flow cytometry analysis of a competition experiment of F023700912(filled circles) and ipilimumab (filled squares) with fixedconcentrations (10×EC30) of (A) hCD80-hFc or (B) hCD86-hFc onhCTLA4-overexpressing CHO-K1 cells. The ligands were detected via thehuman IgG Fc fusion protein. The data generated in these experiments areset forth in FIG. 6 (A-B). These results demonstrate the ability ofF023700912 to block binding of CTLA-4 to its ligands CD80 and CD86,illustrating the ability of F023700912 to affect immune responsesmodulated by CTLA-4 and its interactions with CD80 and CD86.

FIG. 6 (A-B) is a dilution series (start concentration 1 μM, 1/3 serialdilution, 12 pts) of Nb F023700912 (filled circles) and Ipilimumab(filled squares) in 100 μl FACS buffer (PBS (Life Technologies,14190-094), 10% heat-inactivated foetal bovine serum (Sigma, F7524),0.05% NaN₃ (ThermoScientific, 19038)) were added to 1E5 humanCTLA4-overexpressing CHO-K1 cells/well in the presence of a fixedconcentration of (A) FITC-labelled human CD80-hFc-HIS6 or (B)FITC-labelled human CD86-hFc-HIS6 (FITC labelling was performed with adegree of labelling of 3.6 and 2 respectively; concentration=10×EC30,being 3.71E-08 M or 4.35E-08 M respectively) and incubated for 90minutes at 4° C.

After three washing steps (1 washing step=removal of Nb dilutions,addition of 100 μl cold FACS buffer, centrifugation for 5 minutes at 250g), the cells were resuspended in 50 μl cold FACS buffer supplementedwith 5 nM TO-PRO-3 (Molecular Probes, T3605) and analyzed with a FACSCanto.

First, a P1 population is selected based on FSC-SSC distribution.Stopping gate was set on 10000 cells in P1. From this population theTO-PRO-3+ cells (dead cells) are excluded. For this P1/TO-PRO-3-negativepopulation the median FITC value is calculated.

Example 4: F023700912 Specificity Assessment

Specificity assessment F023700912 demonstrated selective binding toCTLA-4. Specificity assessment against BTLA, CD8, PD1, CTLA4, LAG3, CD28was performed on overexpressing cells using flow cytometry, whereas ICOSbinding was evaluated in ELISA as a recombinant protein (hICOS-hFc).Expression of BTLA, CD8, PD1, CTLA4, LAG3, CD28 was confirmed viadirectly-labelled target-specific Abs. Anti-hICOS andanti-hCTLA4/anti-hPD1 positive controls were all positive. No binding tohICOS was observed in the ELISA assays. FIG. 7 (A-H) assesses binding tonegative control L cells, negative control CHO-K1 cells, huCD28+ Lcells, huCD8alpha+ L cells, huLag-3+ CHO-K1 cells, huBTLA+ CHO-K1 cells,huCTLA-4+ CHO-K cells, and huPD-1+ CHO-K1 cells, respectively. Nobinding to BTLA, CD8, PD1, LAG3, CD28 could be observed for F023700912,whereas potent binding of F023700912 was observed on CTLA-4+ CHO-K1cells. The data generated in these experiments are set forth in FIG. 7(A-H). These results illustrated selective binding of F023700912 toCTLA-4 predicting minimal off-target effects upon in vivoadministration.

FIG. 7 (A-H) is a dilution series (start concentration 1 M, 1/4 serialdilution, 12 pts) of batches of half-life extended (ALB0011 buildingblock) Nbs F023700912 (filled circles), F023700925 (filled squares) andnegative control Nb IRR00051 (filled triangles) in 200 μl FACS buffer(PBS (Life Technologies, 14190-094), 10% heat-inactivated foetal bovineserum (Sigma, F7524), 0.05% NaN₃ (ThermoScientific, 19038)) were addedto (A) 2E4 L-cells/well, (B) 2E4 CHO-K1 cells/well, (C) humanCD28-overexpressing L-cells or (D) human CD8 alpha-overexpressingL-cells, (E) 2E4 human LAG3-overexpressing CHO-K1/well, (F) 2E4 humanBTLA-overexpressing CHO-K1 cells/well, (G) human CTLA4-overexpressingCHO-K1 cells/well or (H) human PD1-overexpressing CHO-K1 cells/well andincubated for 30 minutes at 4° C.

After three washing steps (1 washing step=removal of Nb dilutions,addition of 100 μl cold FACS buffer, centrifugation for 5 minutes at 250g), the cells were incubated for 30 minutes at 4° C. with 3 μg/mlanti-ALB0011 mouse mAb ABH00074 in cold FACS buffer for detection of thehalf-life-extended Nbs.

After three washing steps, the cells were incubated for 30 minutes at 4°C. with a 1/100 dilution in cold FACS buffer of PE goat F(ab′)2anti-mouse IgG (Jackson ImmunoResearch, 115-116-071).

After three washing steps, the cells were resuspended in 50 μl cold FACSbuffer supplemented with 5 nM TO-PRO-3 (Molecular Probes, T3605) andanalyzed with a FACS Canto.

First, a P1 population is selected based on FSC-SSC distribution.Stopping gate was set on 10000 cells in P1. From this population theTO-PRO-3+ cells (dead cells) are excluded. For this P1/TO-PRO-3-negativepopulation the median PE value is calculated.

Example 5: F023700912 Nanobody Binding to Human, Rhesus Monkey and MouseAlbumin

F023700912 binds to human, rhesus monkey and mouse albumin, predictingprolonged half-life when compared to non-albumin-binding Nanobodies.Binding to human, rhesus monkey and mouse serum albumin was observed,when analyzed using surface plasmin resonance (SPR). The data are setforth below in Table E. Albumin binding of F023700912 is expected toreduce the clearance of the Nanobody upon in vivo administrationimproving its therapeutic potential.

TABLE E Binding of Nanobody to Albumin. Human serum albumin Rhesus serumalbumin Mouse serum albumin Ka Kd KD Ka Kd KD Ka Kd KD (1/Ms) (1/s) (M)(1/Ms) (1/s) (M) (1/Ms) (1/s) (M) F023700912 9.4E+04 8.8E−03 9.3E−089.5E+04 8.9E−03 9.3E−08 1.2E+05 1.8E−01 1.5E−06 F023700925 3.4E+047.6E−03 2.2E−07 3.3E+04 8.1E−03 2.4E−07 4.8E+04 1.5E−01 3.1E−06Instrument: Biacore T100 (GE Healthcare); Sensor chip: CM5 (IDT160713-2, GE Healthcare, lot 10242599)

Example 6: Nanobody F023700906 N73 Variants

Variants F023701051 (11F01(L11V,A14P,Q45R,N73Q,A74S,K83R,V89L,M96P,Q108L)-FLAG3-HIS6), F023701054(11F01(L11V,A14P,Q45R,N73T,A74S,K83R, V89L,M96P,Q108L)-FLAG3-HIS6), andF023701061 (11F01(L11V,A14P,Q45R,N73Y,A74S,K83R,V89L,M96P,Q108L)-FLAG3-HIS6) were compared to F023700906 fortheir ability to block binding of (A) CD80 or (B) CD86 to CTLA-4expressing CHO-K1 cells. All these variants were able to block bindingof CD80 and CD84 to CTLA-4. Blocking of CTLA4 to CD80 and CD86 wasdetermined for several of the variants. These blocking data are setforth in FIG. 8 (A-B). These results illustrate the feasibility ofvarying the amino acid in position N73 without major impact on theability of the Nanobodies to block binding of CD80 or CD86 to CTLA-4.Such variants will allow for avoidance of deamidation at N73.

Example 7: F023700912 Eradicates Established Solid Tumors in HumanizedMice

Humanized mice (Jackson Laboratories) were implanted with Panc 08.13tumor cells (human pancreatic adenocarcinoma). Mice with establishedtumors (˜100 mm³, n=9-10/group) were treated as follows: 1-Isotypecontrols (hIgG1-2 mg/kg and hIgG4-3 mg/kg); 2-Ipilimumab-N297A (3mg/kg); 3-Ipilimumab (3 mg/kg); 4-Pembrolizumab (2 mg/kg); 5-Ipilimumab(3 mg/kg)+Pembrolizumab (2 mg/kg); 6-F023700912 (5 mg/kg; indicated asCTLA4-Nab 5), 7-F023700912 (15 mg/kg; indicated as CTLA4-Nab-15), and8-F023700912 (15 mg/kg)+Pembrolizumab (2 mg/kg). All the antibodies wereinjected subcutaneously every 7 days for 6 doses. F023700912 wasadministered subcutaneously every 3.5 days for 11 doses. Tumor volumeand body weight were measured every 4-5 days. Shown in FIG. 9 (A-B) areaverage tumor volumes±SEM, individual tumor volumes on day-37, and tumorvolumes in individual mice over the course of the experiment. The tumorvolume for each treatment group is also shown in FIG. 9 (C-J). Average(mean±SEM) and individual body weight changes in each treatment groupwere also measured (FIG. 9 (K-S)). The number of mice that were founddead or humanely euthanized due to body weight loss was indicated as‘#’. ‘↑’ indicated antibody and ‘*’ indicated Nanobody dosing schedule.These data illustrated the ability of F023700912 to induce anti-humantumor response in vivo in animals that harbor human immune cells. Thesedata support the potential of F023700912 in the treatment of humancancer.

Example 8: Binding of F023700912 and F023700925 to Pre-ExistingAntibodies from Healthy Subjects and Cancer Patients

Trivalent reference Nanobody, 013700112 (not modified for reducing thebinding of pre-existing antibodies) demonstrates binding to severalserum samples derived from (FIG. 10A) healthy subjects or (FIG. 10B)cancer patients. Sequence optimized trivalent Nanobody of similar size,F023700912, demonstrates a lower frequency of binding to the same serumsamples. F023700925 comprises the same building blocks as F023700912.Despite the larger size, the pentavalent F023700925 Nanobody exhibits nomore binding to pre-existing Abs than the reference Nanobody 013700112.Binding of pre-existing antibodies to Nanobodies captured on human serumalbumin (HSA) was evaluated using the ProteOn XPR36 (Bio-RadLaboratories, Inc.). PBS/Tween (phosphate buffered saline, pH7.4, 0.005%Tween20) was used as running buffer and the experiments were performedat 25° C. The ligand lanes of a ProteOn GLC Sensor Chip were activatedwith EDC/NHS (flow rate 30 μl/min) and HSA was injected at 10 g/ml inProteOn Acetate buffer pH4.5 (flow rate 100 μl/min) to renderimmobilization levels of approximately 3600 RU. After immobilization,surfaces were deactivated with ethanolamine HCl (flow rate 30 μl/min).Nanobodies were injected for 2 minutes at 45 μl/min over the HSA surfaceto render a Nanobody capture level of approximately 600 RU for trivalentF023700912 and approximately 1000 RU for pentavalent F023700925. Thesamples containing pre-existing antibodies were diluted 1:10 inPBS-Tween20 (0.005%) before being injected for 2 minutes at 45 μl/minfollowed by a subsequent 400 seconds dissociation step. After each cycle(i.e., before a new Nanobody capture and blood sample injection step)the HSA surfaces were regenerated with a 2 minute injection of HCl (100mM) at 45 μl/min. Sensorgram processing and data analysis was performedwith ProteOn Manager 3.1.0 (Bio-Rad Laboratories, Inc.). Sensorgramsshowing pre-existing antibody binding were obtained after doublereferencing by subtracting 1) Nanobody-HSA dissociation and 2)non-specific binding to reference ligand lane containing HSA only.Binding levels of pre-existing antibodies were determined by settingreport points at 125 seconds (5 seconds after end of association). As areference, the samples containing pre-existing antibodies were alsotested for binding to a trivalent Nanobody not modified for reducing thebinding of these pre-existing antibodies (TO 013700112).

Example 9: Epitope Mapping of Anti-hCTLA4 Nanobody by Hydrogen DeuteriumExchange Mass Spectrometry

Contact areas between anti-hCTLA4 nanobody, F023700912 were determinedby use of hydrogen deuterium exchange mass spectrometry (HDX-MS)analysis. HDX-MS measures the incorporation of deuterium into the amidebackbone of the protein and changes in this incorporation are influencedby the hydrogen's solvent exposure. A comparison of the deuteriumexchange levels in antigen-alone samples and nanobody-bound samples wasdone to identify antigen regions that may be in contact with thenanobody.

The human CTLA4 residues most strongly protected from deuteration by thenanobody, F023700912 were VRVTVL (SEQ ID NO: 118; amino acids 33-38 ofSEQ ID NO: 110), ADSQVTEVC (SEQ ID NO: 119; amino acids 41-49 of SEQ IDNO: 110) and CKVELMYPPPYYLG (SEQ ID NO: 120; amino acids 93-106 of SEQID NO: 110). A heat map for demonstrating F023700912 binding to CTLA4 isset forth in FIG. 13 .

TABLE F Amino Acid Sequences (SEQ ID NO: 110) HumanAMHVAQPAVVLASSRGIASFVCEYASPGKATEVRVTVLRQADSQ CTLA4VTEVCAATYMMGNELTFLDDSICTGTSSGNQVNLTIQGLRAMDTGLYICKVELMYPPPYYLGIGNGTQIYVIDPEPCPDSDFHHHHHH HHHGGQ

We claim:
 1. A CTLA4 binder comprising an immunoglobulin single variabledomain (ISVD) comprising the amino acid sequence:XVQLVESGGGVVQPGGSLRLSCAASGGTFSFYGMGWFRQAPGKEREFVADIRTSAGRTYYADSVKGRFTISRDNSKNTVYLQMNSLRPEDTALYYCAAEPSGISGWDYWGQGTLVTVSS (SEQ ID NO:60) that binds to human CTLA4 at one or more of the following residues:(SEQ ID NO: 118) VRVTVL; (SEQ ID NO: 119) ADSQVTEVC; and(SEQ ID NO: 120) CKVELMYPPPYYLG;


2. The CTLA4 binder of claim 1 fused to a half-life extender.
 3. TheCTLA4 binder of claim 2, wherein the half-life extender is an ISVD thatbinds to human serum albumin.
 4. The CTLA4 binder of claim 3 wherein theISVD that binds to human serum albumin is ALB11002 having the amino acidsequence set forth in SEQ ID NO:
 66. 5. The CTLA4 binder of claim 1comprising: an ISVD that binds to CTLA4 comprising the amino acidsequence set forth in SEQ ID NO: 60 wherein X is D or E; a peptidelinker; an ISVD that binds to CTLA4 comprising the amino acid sequenceset forth in SEQ ID NO: 60 wherein X is D or E; a peptide linker; ahalf-life extender; and, optionally, a C-terminal extension alanine. 6.The CTLA4 binder of claim 1 comprising: an ISVD that binds to CTLA4comprising the amino acid sequence set forth in SEQ ID NO: 60 wherein Xis D or E; a peptide linker; a half-life extender; and, optionally, aC-terminal extension alanine.
 7. The CTLA4 binder of claim 5 wherein thepeptide linker comprises the amino acid sequenceGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGS (SEQ ID NO: 65).
 8. A CTLA4 bindercomprising an immunoglobulin single variable domain (ISVD) comprisingthe amino acid sequence: (SEQ ID NO: 62)DVQLVESGGGVVQPGGSLRLSCAASGGTFSFYGMGWFRQAPGKEREFVADIRTSAGRTYYADSVKGRFTISRDNSKNTVYLQMNSLRPEDTALYYCAAEPSGISGWDYWGQGTLVTVSSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSEVQLVESGGGVVQPGGSLRLSCAASGGTFSFYGMGWFRQAPGKEREFVADIRTSAGRTYYADSVKGRFTISRDNSKNTVYLQMNSLRPEDTALYYCAAEPSGISGWDYWGQGTLVTVSSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSEVQLVESGGGVVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTALYYCTIGGSLSRSSQGTLVTVSSA

that binds to human CTLA4 at one or more of the following residues:(SEQ ID NO: 118) VRVTVL; (SEQ ID NO: 119) ADSQVTEVC;  and(93-106 of SEQ ID NO: 120) CKVELMYPPPYYLG.


9. A CTLA4 binder comprising an immunoglobulin single variable domain(ISVD) comprising the amino acid sequence: (SEQ ID NO: 64)DVQLVESGGGVVQPGGSLRLSCAASGGTFSFYGMGWFRQAPGKEREFVADIRTSAGRTYYADSVKGRFTISRDNSKNTVYLQMNSLRPEDTALYYCAAEPSGISGWDYWGQGTLVTVSSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSEVQLVESGGGVVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTALYYCTIGGSLSRSSQGTLVTVSSA

that binds to human CTLA4 at one or more of the following residues:(SEQ ID NO: 118) VRVTVL; (SEQ ID NO: 119) ADSQVTEVC;  and(SEQ ID NO: 120) CKVELMYPPPYYLG. 


10. The CTLA4 binder of claim 1 which is multivalent.
 11. A binder thatcross-blocks a CTLA4 binder of claim 1 from binding to human CTLA4. 12.An injection device or vessel that comprises the CTLA4 binder of claim 1optionally in association with a further therapeutic agent.
 13. A methodfor preventing CTLA4 from binding to CD80 or CD86 comprising contactingCTLA4 with the CTLA4 binder of claim 1 optionally in association with afurther therapeutic agent.
 14. A method for enhancing an immune responsein the body of a subject comprising administering an effective amount ofthe CTLA4 binder of claim 1 to the subject optionally in associationwith a further therapeutic agent.